How to differentiate synthetic and natural sapphire

How to differentiate synthetic and natural sapphire

by Ashutosh Roy

A deep look shows signs of slow crystallization in case of natural sapphires. Sometimes some external elements in very small quantities are visible in original sapphire like most other gemstones.

Sapphire – Natural versus Artificial

Natural gemstones are taken out directly from the marvelous treasures of the mother earth. Then they are only washed, polished and cut into proper shapes. They are directly sold in the market keeping their originality intact without any intervention by human beings. They are never “processed” or “treated”.

Sapphire Diamond Ring

Likewise Synthetic gemstones are gifts of technology marvels and the very process indicates how to create a new form using all natural elements and solutions. The challenge in Synthetic gemstone is how closest it can hold the look and feel of the natural one.

As the time changes real things are getting imitated as a rule of the human nature. May be, its for comfort, fashion or money-making urge of the greedy scientists engaged in the process. We all are habituated in the artificial cooling by air-conditioner. We may see, how an artificial shower pours down in a film. A test tube baby is also generated from a sterilized mother to see a laughing face, who would not otherwise have a natural baby for her thirsty heart. Similar is the case with a gemstone. Remember a synthetic gemstone has got the exact replication of the natural one in terms of physical and chemical properties. The look and feel and the optical qualities also remain the same. In short, glimpse and glitter remain the same.

Now if we consider the case of Sapphire, it’s a birthstone of September; physically it belongs to the variety of mineral corundum. Now for the natural science students, all varieties of corundum excepting the red one are called Sapphire. The word comes from the Greek Sappherious. Astrologically, Sapphire seems to have magical power even for alleviating long-term misfortune and in particular, to cleanse the jumbled up thoughts to generate a wider vision, clarity and self-confidence. It was perhaps invented in the 19th century for crystal watch and today it’s a common phenomenon to use sapphire (natural or artificial) in high value watches because of its glittering appearances.

Synthetic Sapphire

Now lets have a closer look into the synthetic sapphire. It’s definitely very hard like the natural one, which is approximately 9 in Mohs Scale. Synthetic sapphire is made from the crystallization process of aluminum oxide at a very high temperature. The Verneuil technique is used for making synthetic sapphires. Researchers have tried by varying concentrations of Ni2+, Ni3+ and Cr3+ to generate a wide spectrum of colour.

It’s very difficult to distinguish between the synthetic sapphire and the natural one. A deep look shows signs of slow crystallization in case of natural sapphires. Sometimes some external elements in very small quantities are visible in original sapphire like most other gemstones. The inclusions may be finger prints or like feathers or even may be like laces. If you don’t find any of them, try through magnification. Reddish tints, polysynthetic twinnings are very common to natural sapphires. The hexagonal patterned angular lines are found in Sapphire. “Negative Crystals”, the cavities, are found in natural Sapphires. Impurities of any sort are the most common phenomena in case of Natural Sapphire.

If you compare the natural sapphire with that of Synthetic one, you will notice bubble like inclusions. Even feather like inclusions are also possible in case of natural ones. If they are placed under strong light, the shining becomes abnormal. But again its very difficult for the normal eyes to detect. Inclusions of various types can be tested by fiber-optic lighting. In case of synthetic one, the coloring agents give the gemstone its various artificial hues, which are never present in case of natural one. But remember the synthetic sapphire is not that disparaging like most other synthetic gemstones; sometimes even people ask for synthetic sapphires for their jewelries and watches.

Remember the watch glass producers always prefer colorless synthetic sapphire. The Surface diffusion-treated corundum (SDTC), the revolutionary concept, has been accepted widely, for its coating functionality. Even being a processed sapphire, the SDTC has gained enormous popularity. “Cathodoluminescence Analyses” by Prof. K. Ramseyer at the University of Berne, Institute of Geological Sciences, Berne (Switzerland) have contributed to the design of fancy sapphires, which have again been accepted widely though being these fancy sapphires belong to the category of processed sapphire.

Experts suggest, rub a gemstone in your palm and squeeze it between your fingers. The synthetic one will give you a waxy feel. Testing laboratories use different methodologies to identify the synthetics ones. Experienced eyes of gemologists can detect the synthetic one even by naked eyes and by its touch and feel.

The ultraviolet radiation process is highly helpful for identification of Synthetic Sapphire. Sometimes the specific gravity comparison can also help to identify the natural one. The refractive index test is also useful for distinguishing between the natural and the synthetic one. The synthetic sapphire glows abnormally in the Special lighting effect. But again as an exception, even the natural orange sapphire is highly fluorescent. So don’t get confused! The microscopic view of synthetic sapphire shows the “Curved Striae”, which are colored curved bands in the sapphire. UV Fluorescence is used in many laboratories as a Gemological tool to identify the synthetic stones. Some uses the highly complicated testing method like Secondary Ion Mass Spectrometry (SIMS) for testing the natural sapphires. But the caution message is that heating is never a normal procedure to test a sapphire. Richard W. Hughes in “CORUNDUM IDENTIFICATION IN A NUTSHELL”, advises “complete Fe Spectrum of lines at 451.5, 460 & 470 nm. is proof of natural origin”. Perhaps this is the best full-proof solution.

If you are a novice, try to go to a genuine gemstone mart, which is recognized or of immense repute. You may also try your personally known jewelers. Its always preferable to take help of reputed Testing & Research Laboratories like Gem and Jewelry Institute of Thailand (GIT), American Gem Trade Association (AGTA), Gemological Institute of America’s Gem Trade Lab. There are several grievance redressal forums today like “Jewelers Vigilance Committee” (Website: http://www.jvclegal.org) to address and take action on your complains.

So if you really do believe in the myth that sapphire contaminated water even can save you from scorpion bite, try to be sanguine about the originality of the gemstone, else you may even risk your life!

Conflict Diamonds

Conflict Diamonds

by Shweta Dhanuka

Conflict Diamonds are referred to those stones that originate from vicinity controlled by the group of people who are recognized as rebel in the eyes of the government. Such stones are put on the market for sale to provide finances for the illicit and illegitimate action of these rebels, military and terrorist factions. Converted diamond, Blood diamond and War diamond are additional names for this diamond variant.

Conflict Diamonds are referred to those stones that originate from vicinity controlled by the group of people who are recognized as rebel in the eyes of the government. Such stones are put on the market for sale to provide finances for the illicit and illegitimate action of these rebels, military and terrorist factions. Converted diamond, Blood diamond and War diamond are additional names for this diamond variant.

conflict diamondsThese are mostly found in war torn African countries. Sierra Leone, Angola, Liberia and the Democratic Republic of Congo are most severely affected countries by this gemstone. The illegal groups terrorize, injure or kill the innocent citizen to mine the diamonds so as to control the local diamond trade. The brutal wars that happened in Angola and Sierra Leone were very much terrorizing. In the year 1998, United Nations General Assembly came to know about these atrocious actions of terrorists behind the diamond trade. Also, they found that how the profits earned from the diamond trade is used for funding the terror attacks in different parts of the world. Since then they took some measures to control it.

Blocking the Conflict Diamond in the Diamond Market

Combating Conflict Diamonds’ campaign, commenced in the year 1998 uncovered the funding means of terror groups for their brutal activities. World was shocked to learn that the precious gemstone ‘Diamond’ they adore is used to create the violence in different parts of the world. Since then diamond sold by terrorists was named as ‘Conflict Diamond’. People across the globe demanded the actions to block these diamonds entering the diamond market.

As a result, in May 2000 diamond industry representatives, NGOs and United Nation Government officials met at Kimberley, South Africa to establish the method to eliminate the conflict diamond trade and assure the buyers that diamonds they are buying are conflict-free diamonds. This meeting was hosted by the South African government. In this meeting the method to control the conflict diamond sale was initiated. On January, 2001 the new organization, the World Diamond Council was formed. The new council drafted the process and essential documents that would certify the legitimate diamond. The litigious negotiations went on for more than two years between the council, government and NGOs to establish the Kimberley Certification Process, an international diamond certification scheme.

Kimberley Certification Process System

This system came into existence in the year 2003. Since then it is working towards the objective of safeguard of the gemstone market against conflict diamonds entering the legitimate diamond supply chain. It demands for ‘Certificate of Origin’ with every delivery of diamond. ‘Certificate of Origin’ is the only document that can differentiate between the conflict diamonds and other legitimate diamond. It is the well-structured form issued from the government, having the information in accordance with the standards set (in relation with the origin location of the stone) by the World Diamond Council. It acts as a proof that diamonds are created, sold and exported through legal channels.

In order to control the trade of conflict diamonds, government inspects and monitors this important document associated with every export and import and enforces the new laws in opposition to those who fail to meet the terms. It is the sincere effort from the government to stop these diamonds to reach the market. Once it reaches the gemstone market and gets polished then it becomes almost impossible to identify the legitimate diamonds. Therefore, it is crucial to produce the ‘Certificate of Origin’ on every single transaction of the diamond trade by all the countries participating in it. With this certification process the government’s transparency increases as the origin and total cost of diamond is recorded in the government books.

Consumer’s Duty

It is duty of consumer to strongly ask for the ‘Certificate of Origin’ document at the time of purchase. This would ensure that the seller gives the required certificate and guarantee that the diamond being purchased by the buyer is conflict-free diamond. This would in turn spread the message that consumers would not support the countries that furnish finance for the terror group’s activities.

Since thousands of years, Diamond had been known as the symbol of love and affection. It would never come even in the wildest of the dream that diamond could be the means for causing violence and misery in the peaceful world. People with unethical and inhuman intentions like terrorist or rebels have used beautiful gemstone diamond to create the feeling of terror and hatred instead of humanity and love in the past but now it is under control. Thanks to the sincere and dedicated efforts of Diamond Council, United Nations and NGOs that by establishing Kimberley Certification Process the presence of conflict diamond in the World diamond trade is controlled to the satisfactory level. However, every gemstone enthusiast waits for the day when the entire world becomes free of conflict diamonds.

Each and every individual must ask for the ‘Certificate of Origin’ while making the purchase of diamond or diamond jewelry. In this way, each one of us could be satisfied till the bottom of our heart that our hardcore earned money is not directly or indirectly used for creating the violence. All of us have to act together to make this world free of Conflict diamonds and continue the diamonds to be associated with only love, care and warmth.

Sapphire facts

Sapphire facts

by Seema Susheel

The change in color is due to different element present inside the core of the sapphire crystal. For example if there is an element like Titanium then the crystal reflects blue and hence is blue in color. There is no limit to the saturation of colors in a sapphire.

Sapphire facts and buying guide

Sapphire is the royal semi-precious stone which is been used in jewelry from ancient times. There are known facts that many royals have used sapphire on there crowns, brooches, wedding ring etc. The special quality of this beautiful gemstone is that it’s the hardest stone naturally found. The hardness of this semi-precious stone is just second to that of the diamond. The sapphire being hard in nature sapphire jewelry is durable and recommended to be passed upon as an heirloom.

Sapphire – Origin
Sapphire deposits are found in large quantities in Sri Lanka. Sapphire is been found in Sri Lanka from ancient times and even now it’s a popular destination for good quality sapphires. There is a typical orange pinkish sapphire found only in Sri Lanka and it resembles a lotus. Sri Lanka is the largest producer of this beautiful gemstone. Sapphire is also found in countries like Madagascar, Burma, India- Kashmir, America, Thailand and Cambodia.

Sapphire – Type and color
Sapphire RingSapphires are members of the corundum family of minerals. They come in all types of colors from blue to black and all colors in between. The change in color is due to different element present inside the core of the sapphire crystal. For example if there is an element like Titanium then the crystal reflects blue and hence is blue in color. There is no limit to the saturation of colors in a sapphire. The saturation of the color depends on the amount of mineral present inside the crystal. Many times there are combination of minerals which result in different hues and saturation of the same color. Sapphire comes in colors like blue, pink, yellow, colorless, black, white, orange, and brown. Among sapphires no two sapphires look alike. Most sapphires are treated and given heat treatments to make them commercially valuable and improve there clarity and shine. The blue sapphire itself comes in varied colors of blue like the baby blue to deep sea blue, with a mix of green and yellow they form wonderful color combinations. Blue sapphires are the most popular because of its amazing color which has mesmerized even the royals. Even today the blue sapphire is the most sought after colored stone. The pink sapphire is a favorite among jewelry designers who use this stone in combination with diamonds and white gold for amazing creations.

Sapphire – Buying Information
Sapphire RingSapphire is very rarely found, it is much rarer then the diamond, hence the market price for this stone is on a rise. It’s safe and sound to invest in a fine quality untreated sapphire then in any other jewel as there sure to be value add to this stone. The demand is more and the production is not so much to match the demand. A natural uncut, untreated sapphire with fine quality of color and shine is jewels an ardent jewelry lover will surly keep in his collection. There are treated sapphires also available. There is a difference in price among sapphires depending on the color quality, whether its treated or untreated, carat size, shine and brilliance. Though the most popular color is blue and pink the choice of color is a personal choice and with sapphire you can find them in many colors.

Sapphire- Buying shops
As popular and available the diamond is, the sapphire though popular is not very easily available. You can find hundreds of jewelry shops and websites selling diamonds. The same is not with sapphires simply because it’s much rarer then diamond. Few authentic serious gems traders who have set up there shops on the internet is the shopping stop for the ones who want the royal indulgence to be there own. These websites will give you extensive information on the sapphire and also provide you with wide range in prices, sizes and colors. If the sapphire is extremely outstanding with flawless color and shine then its something you can make your own. The price differentiates depending on the quality and the carat size. Once you have decided on the type of sapphire then you can buy it to use in jewelry like finger ring, a pendant or a brooch. You can even go for boutique fashion jewelry sites where in you could select one of the readymade jewelry pieces where blue sapphire or pink sapphire is tastefully used with other metals and stones to create amazing neck pieces and matching ear rings. Bracelets, waist bands, accessories – sapphire has found its use in many items. The price for sapphire jewelry could be similar to the expensive diamond set you were eyeing but the difference is you are paying for the beauty and quality which is rare and one of its kind.

Sapphire Buying – feel the beauty before you make it your own.
There are many gems traders who deal with buying and selling gemstones. These jewelry shops are in this business from generations. Many jewelers are in this business for so long that for then to gauge a quality sapphire is as easy and simple as drinking water. You got to be lucky to find such a shop by yourself but with little effort you surely can come across one where in you can buy the royal blue sapphire and trust the jeweler to give value for you money. You are wishing to buy sapphire to wear it as a locket or for any other use when you are buying just the single stone then you have to look at the clarity of color, size that suits your design and consequently the price. The jewelry shops are the places where the jeweler will take you through viewing different kinds of sapphires colors and sizes. You can see and feel the beauty of the sapphire you buy before making the purchase. This kind of luxury is only for those who can afford to take time off there busy schedules and put in the time and effort to go shop hopping to look for the right sapphire that will win there heart. Once you have found something that you love then it’s easier to shell out money. A purchase like sapphire won’t make you repent in future as its valuable forever.

Helpful Rockhounding Tips

Helpful Rockhounding Tips

by Ritika

Rockhounding is for those who love to collect rocks and minerals from their natural environment as a recreational hobby or sport. It starts when you chance upon a beautiful stone which you pick up. Humans are very curious by nature so your curiosity about its origins is bound to get aroused at some point of time. Talk to a few people and you’ll find there is a whole world of rockhounders there who love to do what you just did but they go the whole gamut.

Rock CrystalsRockhounding is for those who love to collect rocks and minerals from their natural environment as a recreational hobby or sport. It starts when you chance upon a beautiful stone which you pick up. Humans are very curious by nature so your curiosity about its origins is bound to get aroused at some point of time. Talk to a few people and you’ll find there is a whole world of rockhounders there who love to do what you just did but they go the whole gamut.

Rockhounders clubs flourish in practically every town, county and city and there will always be old-timers who will give you important tips and handy hints on how to get the best out of this hobby. Read up on petrology, geology, rocks and minerals and kit yourself out with a rock hammer, gloves, safety goggles, water, a book depicting rocks and minerals and their features, a first aid kit, food for you and fuel for your mode of transport and you are a ready to go rock hounding.

RockhounderBesides the slew of precautions you have read about and been informed about there are a few other aspects to rock hounding that are good to know especially if you are planning to go in to this hobby full time. It would be a good idea to read up all you can about lapidary, working with rocks and minerals, facts to keep in mind about the various characteristics of various rocks and minerals, how best they can be cleaned and polished, tools required for cleaning and polishing etc.

As you gain experience in rock hounding, your collection too keeps growing. Soon you will have quite a nice little assortment of rocks and minerals. There are lots of aspects to cleaning and polishing of rocks and minerals. Given below are a few tips and hints that might help you as you learn on the job.

Did You Know?

* Cleaning Stones is an art by itself. Eyeglass silicon treated tissue removes fingerprints from stones.

* Flush the dirt to the surface using toothpaste that has fluorite. It can penetrate brick, terracotta, ceramics and stone easily. The dirt can then be rinsed off with water.

* Desert roses and best cleaned using a solution of “axion”. Soak overnight, brush gently and rinse in clean water. This is an easy and safe method.

* Ultrasonic cleansers are used by some professionals but there are some stones that must not be cleaned in this manner. They are stones like pearls, lapis, opal, coral, tourmaline, mother-of-pearl, emerald and turquoise, agate, topaz and malachite.

* Fluorite should never be cleaned in warm or hot water because it will wash off the luster and it will never come back. A better idea is to put in ‘muriatic acid’ which will remove the calcite and then rinse in cold water.

* Pyrite, quartz and other silicas are best cleaned with radiator cleaner DuPont No.7. Use one tablespoon for one quart of water then rinse with silute ammonia and a final rinse in clean water.

* A good soak in water and ammonia will clean out lichen and algae from your rock samples.

* If you want to see what’s inside your stone then before you commence faceting drop them in some oil of cassia or cinnamon. All flaws and inclusions will be visible as the refractive index of these oils is very similar to that of most gemstones. The surface irregularities disappear, making it easy to see.

* Jade and other soft stones like aventurine and tiger eye, can be effectively polished using a wet 600 sanding cloth. Once done, apply the No. 1200 metal lapping compound, available at any auto supply store, to one inch of a leather lap and work the stone, you will find that the stone gets a dull polish which can then be given a good shine using cerium oxide or tin.

* Peridot is best worked on suing a 260 to grind, 1,200 for pre-polishing and then with Linde A on a type metal lap or a tin lap.

* Malachite can be cut using a saw. This is soft stone so it’s best to keep away from the direct parallel of the grain by about ten degrees. By doing this you will get the bull’s-eye effect when you dome the stone. Wear a mask while grinding as the flying dust is toxic and grind on a well worn out 600. Give it a final polish with “ZAM on hard felt” the more you polish the better the stone becomes.

* Fire Agate is really a chalcedony which has a layer of iridescent limonite that is trapped in-between the chalcedony layers. You need to be careful when working with fire agate. Start your grinding slowly suing a 100 grit wheel. The “fire” is the dense spot inside where the iridescent limonite is. Once done, grind on a finer wheel so you “fire” is seen more clearly and clover to the surface. Be careful you don’t sand away the “fire”. Finish off with a leather buff using tin oxide.

Interesting facts

* Molten rocks are responsible for the formation of topaz, emeralds, diamonds, and rubies.
* Ground water evaporation is what forms opal, amethyst, quartz and turquoise
* Metamorphic re-crystallization makes garnets and staurolite.
* Of all gemstones jade is the most durable.
* Wear opals, pearls, amber and turquoise carefully as they scratch easily.

These are just a few tips and hints on polishing and cleaning of rocks and minerals. Read up all you can before you commence with the cleaning and polishing for best results.

Star Sapphire

Star Sapphire

by Nasrina Parvin Khan

A good Star Sapphire should be eye clean and have velvet like softness, as opposed to diamond like transparency.

INTRODUCTION OF STAR SAPPHIRE

Sapphire- the heavenly stone of this Earth is one of the most precious stone among the gems.

Sapphire is the single crystal form of Aluminium oxide (Al2O3), a mineral known as corundum. The heat and the pressure depths of the ground help the pure Aluminium oxide to crystallize into beautiful and splendid white gemstone since the age. Small amounts of other elements such as chrome and iron are the reason to turned this white crystal into colorful. Sapphires available in sky blues or sunset colors. The color of sapphires may be blue, red, yellow, pink purple, orange or greenish color.

Rubies are also part of corundum group. There was a debate which stone may be termed as a sapphire for long years. Finally it was decided that ruby-red sapphires would be “Rubies” and all other colors would be “Sapphires”.

Though sapphires are available in various colors, but the most popular color of sapphires is blue.

When we talk about sapphires, most people will think about blue. Sapphires other than blue are known as ‘fancy’. So fancy sapphires referred to yellow, pink, purple, green, black or white sapphires.

The most important characteristic of sapphires is its excellent hardness. Moh’s scale shows the hardness grade 9. The hardness of sapphire placed with ruby just after the diamond. Sapphires are easy to care and handle because of their great hardness.

Usually sapphire occurs in sedimentary limestone, metamorphic marble, and igneous basalt, pegmatite or andesine dikes. Naturally corundum mined from secondary alluvial deposits and rarely from primary deposits.

There are various kinds of sapphires, like- “Blue sapphires”, “Fancy sapphires”, “Padparadsha”, (means lotus flower)-an orange color variety of sapphires with a fine pinkish undertone and very unique “Star Sapphire”.

BLUE SAPPHIRES

The main color of sapphires is blue. It is the most popular color of sapphires also. In the ancient time, every blue gem material was called sapphire. As for example we can say the name of Lapis lazuli. So, the name “Sapphire” derives from the Greek word ‘Sappheiros’, which means blue.

Blue is the most desired color of sapphires. This gems available in all the shades of blue skies, from the deep blue of evening skies to the bright and deep blue of a clear and wonderful summer sky. Blue fascinates all the people. Actually blue is the favorite color of about 50 per cent of the population in this World. This color has a strong association with emotions such as sympathy and harmony, friendship and loyalty. These emotions represent anything permanent and reliable. So, the sapphire blue has become the color of permanent and reliable things. Thus the women in many countries decide on sapphire for their engagement rings.

STAR SAPPHIRE

Star SapphireMost of the blue sapphires are found in the form star sapphires. Star sapphire is a variety of sapphire that shows a star like special optical phenomenon named as “asterism”.

It is a rare variety of sapphires. Nearly 3 stars are discovered in every 100 faceted corundum mined. Though Star Sapphires are more common than the Star Ruby. But finer colored stone with fine star is very rare. Except blue, star sapphire is also available in black.

“Asterism” is a phenomenon by which a star shaped light effect has been shown across the surface of the gem through the reflection or transmission of light.

Star Sapphire is one of the most popular star gems, which shows an illuminated, wavy star bellow the surface of the crystal.

Usually Star Sapphire shows the six legged star effect. But it can shows four to twelve rays depending on the crystal system of the gems. Twelve rays star effect in sapphire is very occasional.

WHAT CAUSES STAR EFFECT

Star effect or “asterism” is caused by the dense inclusions of tiny fibers of foreign particles in gems. Generally, these inclusions are the reason of the reflection of light and form a wavy star like formation, which moves around when the mineral is rotated. All the inclusions in the gem are form via exsolution.

Solid crystal inclusions found within the corundum sapphire. Some sapphires leave holes or empty areas in the host, which filled with liquid, gas or solid. Reflection creates from fibers or fibrous cavity in the crystal.

The inclusions must be long, very thin needle like which called as ‘rutile’. “Asterism” is produced when the light is concentrate into 3 rays that intersects at right angles to the direction of the needles. Thus we get a six-rayed star. Small needles of rutile sometimes called ‘silk’ are oriented inside the minerals in the direction of the crystal growth system. There is relationship between the gem’s growth and the number of rays produced by the reflected light.

The arrangements of needles in a hexagonal pattern produced six-rayed ‘asterism’.

Exsolved inclusions form a pattern in the host mineral to form a star. This pattern remains same in case of sapphire. The rays of star should cross at the top of the sapphire and must be distinct.

QUALITY OF A STAR

The sharpness and the size of the star in sapphire depend on the quality and quantity of rutile needles. We get a better star in sapphire when the rutile packed more densely. Longer needles also produce a better star than the tiny particles. When the quantities of needles are much more, sapphire turned into a low translucent stone and lack ‘asterism’. It also harms the color of sapphire.

CUTTING OF A STAR SAPPHIRE

Cutting is very important to exhibit the star effect in sapphire. Proper cutting helps to extracts the beauty of the gem. To display the star effect in best way, a sapphire must be cut as cabochon with the girdle, parallel to the needles. Medium to high cabochons need to be cut to get a perfect star in sapphire. The domed must be round or oval shaped.

COLOR OF STAR SAPPHIRE

Generally Star Sapphires are available in blue. But other colors can also be seen. The color of ruby is red. Star Sapphires are also available in black, purple, and grey and so on. Varieties of blue colored Star Sapphires are found. Star Sapphires from Sri Lanka are light blue or grey.

VALUE OF STAR SAPPHIRE

The carat weight is not the only factor that decides the value of a star sapphire. It also depends on the body color, intensity and the visibility of the star as well as the strength and sharpness of the star. All six legs of the star should be straight and prominent.

Heat treatment is always used to produce, intensify or lighten color or improves color uniformity and appearance of blue sapphire. But some people preferred untreated, natural stone.

A good Star Sapphire should be eye clean and have velvet like softness, as opposed to diamond like transparency.

The market value of a sapphire is also depends on its origin. Sapphires mined from Sri Lanka are the most valuable.

OCCURRENCE OF STAR SAPPHIRE

Finer qualities Star Sapphires are found in Myanmar (Burma), Thailand, India, Sri Lanka, Tanzania, Afghanistan, Brazil, Cambodia, Malagasy Republic, Malawi, Pakistan, Rhodesia of Zimbabwe and Montana and North Carolina of US. But the best quality Star Sapphires are available in Sri Lanka.

FAMOUS STAR SAPPHIRE

The most famous and largest cut star sapphire is 543-carat “Star of India“. The “Mid night Star”- a black sapphire is also famous one. Both of these Star Sapphires are housed at the American Museum of Natural History in New York City. 330-carat “Star of Asia” at the Smithsonian is another famous Star Sapphire in the world..

Diamond Reset

Diamond Reset

by Shweta

It is usually seen that diamond rings are passed from one generation to other. In this case, it is totally one’s emotions whether to reset the diamond from the old ring into a new ring or a pendent or any other jewelry piece. People by and large do not go in for the reset of family heirloom diamond unless there are some apparent reasons.

Diamond remains beautiful and sparkles forever. Its charm enhances with the passage of time. Once the diamond is acquired it is almost impossible to part with it. However, with the changing fashion trends and style, damage, repair or further enrichment in design it is possible to reset the diamond from one jewelry piece to other.

Diamond ResetIt is usually seen that diamond rings are passed from one generation to other. In this case, it is totally one’s emotions whether to reset the diamond from the old ring into a new ring or a pendent or any other jewelry piece. People by and large do not go in for the reset of family heirloom diamond unless there are some apparent reasons. Sometimes, because of obvious reasons like setting smash up or ring size issues the gemstone has to be reset. Also, it is very common to see that after divorce females tends to go for diamond reset as they don’t wish to keep any memories from their past relationships. They cannot let the diamond go so they reset the precious stone in pendent changing into a totally new jewelry piece having no reminiscences of the previous marriage. With the help of modern technologies it is possible to reset the diamond into any other jewelry piece without causing any damage to the precious gem. It is completely one’s own personal decision to whether reset the diamond or not.

Diamonds are valuable hence; need to be handled very carefully. Prior to changing the jewelry by diamond reset, it is crucial to first put in deep thinking as what change is required and why? For example- Place colored precious gemstones around the diamond giving it a more splendid look or change the yellow gold setting with white gold or platinum to give more enhanced glance to the stone. Also it might be the case where the present setting is uncomfortable, the gemstone knocks against everything that comes into contact and the wearer has the fear of cracks to appear on the precious stone with the continuous knocking. If the diamond size is more than one carat then only it is suggested to go in for the resetting else it is not worth the cost and risk involved in it. This analysis of facts and thoughts shall enable in taking the right decision as whether to reset the diamond or not and the purpose behind the reset would be achieved or not.

Once the firm decision is made to reset the diamond then there are certain essential steps to be implemented. The first and foremost step is to look for the reliable jeweler who would do the changes in the jewelry pieces. While selecting an individual or company for diamond reset ask for the reports that give the precise details about the diamond like the color, inclusions, carat weight, size and flaws etc. These specifications would act as proof that the gemstone is the same in the new jewelry piece. Also lab report must be taken to ensure the reliability of the jeweler. It is very important to acquire these bona fide documents before handing over the precious stone.

Second step involves asking for the information about the gemstone.

  • Where shall be the resetting done?
  • In case it is to be sent to some other location then what is their respective reliability?
  • While the diamond is in the jeweler’s possession, is it insured for theft or any other damage?
  • The know-how, skill and certification of the individual who shall do the required changes with the stone?
  • How much time it would take to get the new jewelry piece with the reset diamond?
  • Have any other diamond resetting done in the past or going on in present?
  • How the resetting is done? The clarity and frankness in the answers of these questions could explain the credibility of the jeweler.

These two steps would help in knowing the jeweler and his motives. In case the jeweler is not willing to answer these questions or give the required documents then surely he is not the right person. His credibility is doubtful. Hence, it would be wise not give him the precious diamond for resetting. If he is truthful and his intentions are clear then he would provide all the asked information and also shall explain the process of diamond reset noticeably well to his clients. He would also suggest the best designs depending upon the choice of the wearer.

Third step is to select the suitable new design. Any design selected must have the prong setting. This is the ideal setting as with prongs around the solitaire makes it safe and well placed. Always make sure that prongs are adequately long to hold firmly the girdle of the diamond. From all four sides the prongs must be tightly held against the gemstone. Stone more than one carat weight is valuable and expensive thus its safety in the design setting is very important to be considered.

The last fourth step is to check the finished jewelry. Once the final ring or pendent or any other selected jewelry piece is handed by the jeweler after the diamond reset check for the setting carefully. Use the magnifying glass to make definite that the precious gemstone is placed with the accurate side up and is in level within the prongs. Then tally the diamond specifications with the details mentioned in the report (the same report jeweler gave before taking the diamond for reset). This is to ensure that the diamond in new design is the same.

Diamond reset is the mode of maintaining the interminable beauty always in accordance with the fashion. However, style and trend keeps changing with time. Umpteen efforts must be taken before deciding for stone resetting because no damage should be caused to this precious gemstone because “Diamond is the everlasting asset”.

Complete guide for Rockhounds

Complete guide for Rockhounds

by Ritika

Here is a bird’s eye view on the ever-popular hobbies of the Americans – Rock hounding. The aim of this article has been to throw light on the various important aspects of rock hounding like the seasons and time that are best suitable for rock hounding, cost, tools and equipments required for rock hounding, a peek into the history of rock hounding and last but definitely not the least, some of the major regional attractions for rock hounding. We aim at providing our readers a set of guidelines for safe, legal and responsible rock hounding. The tips provided here may be greatly helpful for our rock hounders to ensure they have successful outings.

Summary: Here is a bird’s eye view on the ever-popular hobbies of the Americans – Rock hounding. The aim of this article has been to throw light on the various important aspects of rock hounding like the seasons and time that are best suitable for rock hounding, cost, tools and equipments required for rock hounding, a peek into the history of rock hounding and last but definitely not the least, some of the major regional attractions for rock hounding. We aim at providing our readers a set of guidelines for safe, legal and responsible rock hounding. The tips provided here may be greatly helpful for our rock hounders to ensure they have successful outings.

OVERVIEW

Rockhounding toolsAs you all may be aware, Rockhounding refers to the fascinating treasure hunt and recreational collecting of rocks and or minerals from their natural environment. Rock hounding can be your greatest excuse for playing with nature in a harmless manner. There are several ways that one can resort to rock hounding. Some collectors go in search of certain types rocks like volcanic rocks or meteorites. Others collect fossils or mineral specimens. There is also gold planning or prospecting of gold. Apart from gold minerals, gems and precious and semi-precious stones are all hot pursuits of rock hounders.

If we trace the early history or rockhounding, we find that some of the early rockhounders were prospectors who were on the search for precious minerals and gemstones that can be used commercially. However, as time passed, more and more people have taken to rock hounding as a recreational pass-time as they have been inspired greatly by the beauty that the rocks and minerals provide.

Whether you are an experienced and trained rockhound or prospector, there can be no doubt that loads of fun, adventure and may be various hidden treasures are in store for you. However, prior to embarking upon such adventures, it is important that you are equipped with the right information and accessories. Learning a lot about petrology, the study that would help you gain knowledge of the various rock forms and the conditions on which they form, would be of immense help to any rock hound. Apart from petrology, an in-depth knowledge of geology would also be of immense value in rock hounding.

Much of world’s famous rock hounding takes place in the United States, especially in cities like Alaska, Arizona, California, Colorado, Hawaii, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington and Wyoming. Most of these states have an abundance of minerals, precious and semi-precious stones in their mountains.

The most common materials that are being sought after by rock hounds are:

* Agate
* Jasper
* Limb Casts
* Obsidian
* Petrified Wood
* Thunder Eggs

All these materials have formed as a result of processes that are at least a thousand years old. For instance in Oregon, millions of years ago various volcanoes that erupted in the region of Central Oregon led to volcanic ash being deposited on the steep slopes that mixed with the tropical rains and created mud flows that swept across the landscape devouring plants and animals and storing them inside as fossils.

Similarly, in Washington a continuous phase of volcanic eruptions that resulted in the oceanic plate being submerged under water along with water rich rocks under the continental plate. Since lava rocks and ash have rich silica content, this gives a good chance for agate formation in the area. This action has resulted in some of the finest agate reserves in the area including the well-known Ellensburg Blue Agate.

IMPORTANT REGULATIONS TO FOLLOW WHILE ROCK HOUNDING

Prior to choosing any site for rock hounding, there are various important points to remember. They are:

* The rock hound should determine if the site selected is located within the National Forest Land.
* It is important to find out if rockhounding is legally permitted in the area
* The rock hound should also find out if the mineral rights in the site are privately owned. The above information will be available with the local District Ranger Offices.
* Semi-precious stones, mineral specimens and common invertebrate fossils can be collected from public lands in reasonable quantities for personal use.
* Vertebrate fossils can be collected only with requisite permits.
* Collection of rock materials for commercial use is prohibited.
* No mechanized tools or explosives can be used during rock hounding. Only shovels, picks, chisels, rock hammers and crowbars are allowed.
* Most importantly, every rock hound must solemnly adhere to the Rock hound’s Code of Ethics to ensure that the entire rock hounding experience is a pleasant and memorable one for everyone involved in the adventure.

ROCKHOUNDING TOOLS AND SUPPLIES:

There are thousands of rock hounding accessories and tools in the market. All rock hounders must ensure that they are well equipped with the best and safest rock hounding equipments. The rock hounding kit must possess essentials like probes, digging tools, rock hammers band crevice tools. Various modern rock hounding tools are available like the Rock pick, which has a hammer on one end and a sharp pointed pick at the other, making it suitable for freeing specimens, busting rocks and digging in the dirt.

All rock hounders must possess a map of the desirable location that is highly informative and provides accurate details about the minerals and rocks available in the site. Various pocket guides to rock hounding are available in the market that throw an ocean of light on the various aspects of rock hounding like fossil search, mineral hunting, gem search and gold are prospecting.

By following the above mentioned guidelines we assure you that your journey through the various blazing deserts, winding rivers and various geologic wonders would create one of best and most fruitful rock hounding adventures you have ever had. It would also kindle your interest in this search for the untouched treasures of Mother Earth and motivate you to venture out to those out-of-the-way places. Happy Rock Hounding!!

Important Sapphire Mines In The World

Important Sapphire Mines In The World

by Ritika Changrani

Sapphires are beautiful stones found in myriad colors like blue, yellow, orange, purple and even pink. The most expensive sapphires are not those which have been heat treated but those which have been mined as nature intended them to be – straight from the depths of the earth. These are the rich & vibrant blue sapphires. Sapphires are mined all over the world. There are sapphire mines in India, Ceylon, Burma, Australia, Brazil, Thailand, Vietnam, USA, and Africa.

Sapphires are mined all over the world. There are sapphire mines in India, Ceylon, Burma, Australia, Brazil, Thailand, Vietnam, USA, and Africa.

Sapphires are beautiful stones found in myriad colors like blue, yellow, orange, purple and even pink. The most expensive sapphires are not those which have been heat treated but those which have been mined as nature intended them to be – straight from the depths of the earth. These are the rich & vibrant blue sapphires.

sapphire minesCutting a sapphire is difficult as a sapphire has many colors and a cutter faces the dilemma of trying to get the best in brilliance, depth of color and line while cutting the gems. A sapphire is valued depending on its size or carat, the color, clarity and the cut, or which we know and refer to as the Four Cs.

The chemical composition of the sapphire is dialuminum trioxide (Al2O3) which is a colorless and clear mineral. The stones get their color from the impurities that are present within it. For example, yellow comes from the iron so yellow plus titanium becomes blue and the red comes from chromium. Red sapphires are what the world knows as rubies. Titanium oxide is the most commonly found impurity which looks like silk needles. This is where the above mentioned heat treating comes into play. If the stone is treated to a heat reading 1700-2000 degrees Centigrade, the needles dissolve, the haze in the gem clears and the gem then acquires a brilliant look.

Sapphires are mined all over the world. You will find sapphires in India, Ceylon, Burma, Australia, Brazil, Thailand, Vietnam, USA, and Africa. The sad part is that the best sapphires are found in the strife ridden areas on the India – Pakistan border where the political situation is not one to be stepped into lightly. The Kashmir stones are the most valuable sapphires. The oldest mines are in Sri Lanka but the blue sapphires are mostly from Australia and Thailand. Madagascar will give you superb pinks and yellows and of course blue. Brazil has pink, purple and blue stones while in Tanzania you will find yellow, orange and blue.

The Aussie sapphire

The mine is at Reddestone Creek in Australia and this mine has seen plenty of mining over the last so many years. Mining right in the path of the stream is not allowed anymore since this was affecting the quality of the water. The commercial aspect of the Aussie sapphire commenced sometime in 1998.

Madagascar

Ilakaka and Sakaraha are situated a little south of the island Madagascar near a place called Toliara or Tulear. Since its discovery in 1998, the mine has seen active mining and trading from all over Madagascar is conducted here. Go past the desert southwards and you will reach a place called Andranondambo. Known at one time as Fort Dauphin, Tolanaro is a metasomatic sapphire mining area for blue sapphires where, in 1994 the first sapphires of gem quality were found.

Spokane Bar

Along the Missouri river on the banks of Hauser Lake, lies the Spokane gravel bar. It was named by geologists who were mapping the area in early 1900’s and they came upon a sapphire cache. Hauser was one of the territorial governors of Montana and the lake is named after him. This lake has played a very important role in the history of sapphire mining. The story goes that the governor and his partners were panning for gold. The sluice boxes got blocked by some heavy stones so the miners sent it to England where it was confirmed that these are sapphires and quite priceless. Today sapphires of every color and hue can be found at Spokane bar. Most common among these are the blue/green sapphires.

North Carolina

The Old Presley Sapphire Mine is situated near Canton in North Carolina in Haywood County. In western North Carolina this is the oldest mine in operation and its claim to fame is the discovery of 1445 carat sapphire which was called the Star of the Carolinas. Now the mine has plenty of moonstones, sapphires and various other precious stones waiting to be found.

Montana

In Montana the first mined Sapphires were found at the Rock Creek deposit around 1892. Earlier it was abundant in sapphires and today is noted as the only place that has quantities enough to make it a commercial venue for sapphires. Mining for gems is an activity that has been enjoyed by visitors and even Montanans themselves these days. Rock creek is the only one out of the four areas of sapphire deposits in Montana where the gem has such a fine quality and a variety of sharp colors. With brilliant jewelry being the preferred type among people, the Rock Creek sapphire has found its own niche market. With heat treatment also easily done, this industry has really taken hold. The other sapphire deposit region of Montana is Philipsburg. At the Sapphire Mountain and at Gem Mountain, mining is open to the public. This is a popular destination for sapphire mining and hunting.

Sri Lanka

Mining on the island of Sri Lanka goes back at least 2000 years. This island has its own heritage in the mining arena. The island is called Gem Island or “Ratna Dweepa” because of the large variety of gems found here. You will find everything from peridot to moonstones to garnets and topaz. Today Sri Lanka is best recognized for it’s the sapphires called the Ceylon Blue, and the sapphire called Padparadscha which has a beautiful and unique orange pink pastel soft color, very similar to the Lotus flower found on this island. The traditional Ceylon mines are near Ratnapura which is located southeast of Colombo about 100kms away.

Sapphires are found everywhere in the world. This stone has numerous astrological aspects to it also. There are varying opinions about its use and wearing it is considered beneficial for some while it is known to bring bad luck to others. But superstitions not withstanding, the blue sapphire is a beautiful stone with brilliance few can match.

Precautions and Care of Diamond

Precautions and Care of Diamond

by Mark

Diamonds are a woman’s best friend. A diamond has the lustrous shine that attracts everyone towards it. The shine and glow of this gemstone can be retained forever with appropriate precautions and care. It is the hardest stone, with a hardness of 10 on the Moh’s scale. Even then it is possible for a diamond to get chipped, scratched or damaged in a piece of jewelry. This could be due to improper setting techniques during manufacturing or careless use by the wearer. Therefore, it is very crucial to take safety measures to avoid spoiling the stone. This article would give the reader the general know-how about all the aspects that would help in preventing the gemstone from the any kind of damage.

Cleaning:

It is one of the most important features of keeping the diamonds shimmering. Depending upon the usage of diamond jewelry the frequency of cleaning is determined. If the diamond set is worn occasionally for exclusive parties then it may not be required to clean at all but if the jewelry is worn daily then it is essential to clean it twice a year. Cleaning has to be done with utmost patience and care.

DiamondSpecial brushes are available in the market designed for cleaning diamonds. In case it is not available then look for small and soft brush like an eyebrow or a lipstick brush. Use this brush, mild soap and water for cleaning. First step of this procedure is to prepare a solution by mixing Luke warm water and mild soap. Place this solution in medium size glass bowl. In the center of the bowl place the diamond jewelry. Soak it for few minutes then give an extremely gentle rub with the brush. Make sure to clean the stone from the bottom as this place is more prone for dirt and oil accumulation. Then give a thorough rinse with clean water and wipe it off with a cotton cloth. During the entire process always hold the jewelry from the edges.

The jewelers would use diluted ammonia to clean the gems but when cleaning at home it can be replaced with a mild cleanser or one pinch of cooking soda. Also special jewelry cleanser is easily accessible in the market. These too could be used instead of mild soap. Before using this cleanser always ensure to read the instructions to know whether it is suitable for Diamond cleaning or not. Also make certain to follow all the directions given in the leaflet. Some people would use old toothbrush for cleaning but the eyebrow or lipstick brush is a better choice as its bristles are softer. Apart from cotton any other fabric must be avoided for drying the jewelry after it is rinsed with water as cotton cloth soaks water very well. Some people also use ultra sonic cleansers for cleaning the diamond jewelry but it is recommended less as the waves emitted are not good for the stone in the long run.

Storage:

When the jewelry is not used it should be stored properly in its respective place like a jewelry box or any other box having the soft cloth inside. Every single stone jewelry must have its own assigned place to store else when all the jewelry pieces are kept in same box then there is high proximity of stones getting scratched or some other damage could happen. Single stone earrings, pendants or rings having more than 2 carat stone should be wrapped in the cotton or tissue and then stored in the jewelry box. This is the ideal safety measure to protect the big size stone mounted in the jewelry piece from getting damaged.

Vital Guidelines:

These guidelines are important to follow to protect the diamond jewelry from all sorts of danger and damage that could take place due to unforeseen circumstances.

  • Diamonds are placed in the jewelry setting with the help of prongs and mountings. With regular use the prongs tend to get loose sometimes and gems starts shaking. If this is ignored then there are chances that the precious gem falls out of the jewelry anytime and the wearer can’t even notice it at that instant. Therefore, all the jewelry should be taken to the jeweler occasionally to tighten the prongs and mountings.
  • At the time of physical exercise it is suggested not to wear the gemstone jewelry to avoid the chances of knock out, breakage or scratches on the stone. Similarly, while playing outdoor sports one should not wear diamonds.
  • By mistake if the diamond ring falls on concrete then always check whether the claws are intact and stone is tightly held in its position or not.
  • In one finger always wear only one ring and ensure the diamond do not rub with any other ring’s stone. Females tend to wear rings in all the fingers as a result it is obvious that metal of rings stroke next to one another or the gemstones mounted in the rings. Metal rubbing with metal is still better than diamond rubbing against diamond or any other gems.
  • Avoid cleaning all the diamond jewelry in the hand-basin, the heavy flow of tap water may wash away stones that may have become lose while cleaning.
  • Always ensure to remove the jewelry having diamonds at the time of doing household work, gardening, and playing water sport, outdoor games, sleeping and bathing.

Diamonds are certainly forever, but to keep the enduring beauty of these durable stones intact it is important to take care of them. A little effort and precautions can go a long way in ensuring the diamonds retain the glitter forever.

Lab identification of Sapphire

Lab identification of Sapphire

by Erum Qureshi

Sapphire, derived from the Greek word sapphirus, literally means blue. Many people will find it difficult to believe that ruby, with its intense red color and the royal blue sapphire are the same mineral corundum composed of oxygen and the light metal aluminium.

Ideal sapphires are stones of an intense blue verging on the violet. Large sapphires are more common than large rubies. Let us look at the physical properties of the mineral species corundum to which the sapphire belongs.

Species

sapphire

Metallic oxides are responsible for imparting color to this mineral. If not for these impurities present in the crystal structure of corundum, it would be colorless. Red stones of the corundum species are termed as rubies and all other colors are known as sapphires with the color prefix.

Corundum is found in many colors besides red and blue. Colorless Sapphire is called leuko-sapphire, yellow, violet, green and even brown colors may be found. Also sometimes found is a very rare and highly valued orange color, known as ‘padparadscha’ (from the Sinhalese word for ‘lotus flower’). Occasionally color-changing sapphires can be found; asterism and star-stones come in almost all colors.

Hardness

Hardness is the same as ruby (9 on the Moh’s scale) and also differs differently in different directions (an important factor which need to be kept in mind during cutting).

Determination of Specific Gravity

Specific gravity of a gemstone is the ratio of its weight to the same volume of water. Since there is no definite demarcation between ruby and sapphire, the same tests for measuring specific gravity are used as those for ruby. The Clerici solution is used to measure the specific gravity of sapphire as this solution is the heaviest among the high-density liquids available. The stone when suspended in the Clerici solution should be clean and dry as the tweezers and other apparatus used for the test. Care is should also be taken that these are free from other organic solutions before immersing the gem in the solution. Natural sapphire will have an SG approximating 3.99. An exception is iron-rich yellow, green and blue-green sapphires, which may have specific gravity as high as 4.00. Once the SG is confirmed to be that of corundum, the gemologist moves on to the next step.

Refractive Index

Sapphire Stone

Light rays leaving one medium and entering another obliquely seem to bend a little at the place of contact. This is called refraction of light. During gem testing, measuring the refractive index or RI helps the gemologist observe the indices of refraction of light on a particular species of gemstone. The refractive index for sapphire is measured exactly in the same way as that of ruby, both being of the same species, their RI is the same. Spot readings are taken for cabochon cut sapphires; faceted stones are placed facedown on the glass of a Refractometer with a small amount of contact liquid and the reading is taken. The RI of sapphire will be 1.76 to 1.77.

Double Refraction

When a ray of light enters a crystal having a Trigonal system in directions other than the optic axis, it splits into two distinct rays. This is known as double refraction. The Sapphire, being of the Trigonal crystal structure shows two indices of refraction in a polariscope. These are known as the ordinary ray and the extraordinary ray. Birefringence is the difference between the highest and lowest refractive indices. Sapphire has a birefringence of – 0.008, with a negative sign because the ordinary ray is f greater value.

Pleochroism

The fact that there are two rays in these stones has an effect on color, for each of these rays absorbs light differently and as the stone is turned it shows a slightly different shade of color. This effect known as Dichroism, is seen fairly well in sapphires of all colors except in colorless and yellow stones. The most attractive color is that of the ordinary ray in sapphire, which is a deep royal blue.

Absorption Spectra

The absorption of colored stones is in well marked bands or finer dark lines which cross the otherwise continuous spectrum, obliterating certain colors or wavelengths when white light is transmitted through or reflected from the stone. The spectroscope is an instrument that determines the wavelength of the absorbed light. The wavelength is measured in nanometers (symbol nm) or angstrom symbol ?. The spectrum most common to blue, green and yellow Sapphire is the iron spectrum. It consists of three lines of increasing intensity at 451, 460 and 470 nm. The absorption spectra of sapphire (in nanometers):

Sapphire ,blue (from Australia) : 471, 460, 450.
Sapphire, blue (from Sri Lanka) : (450)

Note: Strong absorption lines are in bold letters; weak ones are in parenthesis.

Fluorescence

In the case of blue sapphires, UV fluorescence is practically non-existent. Except maybe Sri Lankan sapphires, which have chromium traces. These show a red or orange glow under long wave and weak blue glow under short wave.

Microscopic Examination

Without doubt the final and most determinative test to decide the authenticity of any gemstone is its examination under a microscope.

Gemologists rely on their expertise and experience to spot the inclusions before taking the final call on the authenticity and grade of a gemstone. The best stones are those with no major color zoning problems, which are well-cut, eye clean and most importantly of an intense blue color. Inclusions (irregularities in the crystal structure and internal flaws) in sapphire are straight angular growth lines following the crystal faces.

Included rutile needles or hematite plates are called ‘silk’, which bring about a soft sheen in the stone. When such a stone is cut en cabochon these rutile needles or ‘silk’ brings about the rare cat’s eye effect or the very desirable asterism (a six rayed star that shimmers above the stones surface when it is moved).

Rhombohedral twinning and boehmite needles are inclusions exclusive to natural corundum and have never been observed in flux grown synthetic corundums. Inclusions typical to synthetic sapphire are curved growth lines (thin striae or bands), gas bubbles and dense clouds of extremely fine rutile silk in star stones. These clouds do not show the straight angular zoning patterns that natural stones show but have curving bands instead.

Treatment and look-alikes

Through heat treatment at temperatures of about 1700-1800 degrees C, some cloudy sapphires, non-distinct in color, can change to a bright blue permanent color. Sapphires can be confused with benitoite, indicolite, iolite, spinel, tanzanite, topaz, zircon and even blue glass. Some imitations are made using doublets, blue cobalt glass with a crown of garnet or a crown of green sapphire and a pavilion of synthetic blue sapphire.

Today, synthetic sapphires having properties identical to the natural stone are being produced commercially.