Gemstone Articles from AJS Gems

  • An exceptional 7.90 ct mint garnet from East Africa, certified by GemResearch Swisslab as tsavorite garnet due to its chromium content and excellent color saturation.
  • We recently acquired a parcel of rough stone from Bekily and cut an extraordinary 10.31 ct cushion cut. This gem has been certified by The Gemological Institute of America (GIA). In addition, GIA has issued a special letter identifying this as a notable gemstone.
  • This 10.14 ct spinel is the finest of the fine red spinel from Mahenge, Tanzania. Top color and clarity and beautifully fashioned in an elegant trillion shape.
  • This 6.02 ct spinel is an exceptional example of the rare spinel from Mahenge, Tanzania, with a cherry red color and excellent clarity. Certified by GRS.
  • One of the finest Tsavorite Garnets we have ever owned is a 4.17 ct cushion cut from East Africa. This gem is a bright chrome green with exceptional clarity.
  • A rare and unique 11.16 ct star spinel from Tanzania, certified by GIA as natural and untreated.
  • GIA has issued a special report on this gem, noting that "The large size, highly saturated reddish purple color and high degree of transparency make this a notable cobaltocalcite."
  • Cobaltocalcite is a rare form of calcite colored by traces of cobalt. GIA has issued a special report on this 11.45 ct Cobaltocalcite, identifying it as a notable gemstone.
  • Cobaltocalcite is a rare form of calcite colored by traces of cobalt. GIA has issued a special report on this 13.03 ct Cobaltocalcite, identifying it as a notable gemstone.
  • One of the prides of our collection is a 12.16 ct Mandarin Spessartite Garnet from Nigeria, certified by GemResearch Swisslab.
  • We recently acquired a rare 8.60 ct unheated white sapphire from Ceylon, certified by GemResearch Swisslab.
  • A very fine royal blue sapphire from Mogok, Burma in a rare 5 carat size. Completely untreated and certified by GRS.
  • One of the finest Tsavorite Garnets in our collection is a 5.58 ct cushion cut from Tanzania. This gem is a bright chrome green with excellent clarity.
  • One of the finest Grandidierites in our collection is a 1.12 ct transparent gem in a saturated blue-green. GIA has issued a special report on this rare stone.
  • Transparent Grandidierite is very rare in sizes over 1 carat. GIA has issued a special report on this exception 2.30 ct Grandidierite.
  • This very rare Burmese Ruby has been certified by both GemResearch Swisslab (GRS) and Gubelin Gemlab. Both labs have issued special reports on this important gem.
  • Fine colored gemstones have traditionally come from Asia and South America, particularly Sri Lanka, Burma and Brazil. But more recently, the important new gem discoveries have been made in Africa.
  • This chart shows the relationship between size (diameter in millimeters) and carat weight for round diamonds.
  • These charts show the relationship between size and weight for different gemstone varieties in various shapes. Since gem varieties vary in density, two 1 carat gemstones may show a significant difference in size.
  • An extraordinarily large paraiba tourmaline from Mozambique, with remarkable clarity (graded loupe clean). Certified by GIT.
  • An exceptional 2.21 ct demantoid garnet from Babrovka, Russia. Excellent saturation and outstanding clarity and disperion. A charactertistic horsetail inclusion is visible under magnfication.
  • This 4.54 ct Grandidierite is one of the largest transparent specimens known in the world. The Gemological Institute of America (GIA) has issued a special report on this gem.
  • We recently acquired a very rare 11.55 ct red topaz from Ouro Preto, Brazil, certified by Gubelin Gem Lab.
  • This month's feature is on a major new sapphire find in Sri Lanka. Material from the new mine should start to reach the market soon.
  • This month we look at the rare garnets from East Africa; tsavorite, umbalite (rhodolite), color change and malaia.
  • This month's feature is on Aquamarine, the blue or turquoise variety of beryl. Learn about color, clarity and cutting grades for this fine gem.
  • This month we look at one of the most fiery of colored gemstones, natural zircon. The most popular color of zircon is blue, Blue zircon is produced by low temperature heating, but only some of the Cambodian and Burmese zircon will turn blue when heated.
  • Rubellite is the name used for the pinkish-red to violet-red tourmaline. It is one of the rarest of all tourmalines and is valued for its intense color. Recently we acquired some bright pink reds from Mozambique that are wonderfully vivid.
  • Aquamarine, the blue form of beryl, belongs to the same mineral family as emerald. But aquamarine has its own unqiue charm, and is evaluated quite differently for color, clarity and size.
  • Aquamarine, the blue color of the mineral beryl, is one of the few fine gemstones that can be found in large sizes at affordable prices. Learn about prices on high quality natural aquamarine.
  • This month our feature article is on fine gemstones under $500. Yes, it is actually possible to buy fine gems under $500 without compromising on quality! Also in this month's newsletter: the discovery of a vast gemstone treasure under an ancient temple in South India and information on the upcoming Hong Kong gem show.
  • This month we introduce our new website -- welcome to the new AJSgems.com. Also in this month's newsletter: notable gems from our collection; news from AJS and the gems world; and answers from our gem experts to customer questions.
  • This month's feature is on Fine Sapphire from Madagascar. See our latest acquistions, read all the news from the gems world and get answers to your questions from our gem experts.
  • This month we have a special offer on Fine Burma Ruby -- 20% on all the rubies in our collection! Take advantage of our one time offer to acquire a rare investment gem.
  • Red is one of the rarest colors in the gems world, and the vivid raspberry color of rhodolite garnet is quite unique in the gems world.
  • Pink is one of the most popular hues in colored gemstones, and few other colors offer such a wide range of choice. Learn about the choices in pink gems.
  • Some sapphires have had their color enhanced by beryllium diffusion. Only a small number of gemological labs can detect this treatment, and consumers should be aware that any heated sapphire may have been diffused.
  • Learn about the many choices and color variations in pink gems, including sapphire, spinel, tourmaline, kunzite and morganite.
  • Few gemstones occur in a vivid aqua blue. The main choices are paraiba tourmaline, blue apatite and gem silica.
  • Blue sapphire is one of the classic colored gemstones, combining vivid color with excellent hardness. Due to its timeless appeal and limited supply, blue sapphire commands a premium price in the market. Now that blue sapphire has also become popular for engagment rings, demand and prices have continued to rise.
  • Rubies from Burma are generally regarded as the finest in the world. They are famed for their pure red color -- a color referred to as pigeon's blood -- and a unique fluorescent quality
  • Thailand is a shopper's paradise, and gems and jewelry are excellent values. But finding a trusted dealer is critical when you're making a major purchase.
  • Australia is one of the great gem markets in the world, and Australians have a deep appreciation for fine gemstones, beyond the local diamonds, sapphires and opals.
  • One of the rarest colors in tourmaline is a bright yellow known in the trade as canary tourmaline.
  • Cat's Eye Gems display a unique optical phenomenon that resemebles the slit eye of a cat. Fine specimens are valued by gem collectors, especially cat's eye chrysoberyl.
  • Certification by independent gemological laboratories now plays a key role in the international gemstone trade, providing assurance to both buyers and sellers.
  • Sri Lanka has been producing fine sapphire for centuries, and many of the world's most famous sapphires were found there.
  • Chrome tourmaline, like tsavorite garnet, is an intense green gemstone found only in East Africa.
  • The chrysoberyls are famous, and include 2 of the most important varieties in the gems world -- alexandrite and chrysoberyl cat's eye. But even the ordinary yellow-green chrysoberyl is a fine gemstone, with excellent hardness and brilliance.
  • Chrysoprase, the apple-green variety of microcrystalline quartz, is one of the rarest members of the quartz family. Fine material displays very good translucency.
  • Citrine is the name used for the the yellow to gold color of quartz. It can also be found in orange and orange-red colors, sometmes sold under the name Madeira citrine. Since quartz is a very common mineral, gem-quality citrine is very affordable and can often be found in large sizes.
  • Clarity standards for colored gems are quite different from those for diamonds. Learn how gem dealers grade clarity for colored stones like ruby, sapphire, emerald and aquamarine.
  • We specialize in serving gem collectors who search out the rare and unique gemstones that are likely to increase significantly in value over time.
  • Diaspore is a rare color change gem from Turkey, that displays a subtle color change from a kiwi-like green in daylight to a champagne color in incandescent light, and a light purplish-pink under low intensity lighting such as candelight.
  • Rare blue color-change garnets were first discovered in the Bekily district in southern Madagascar in 1998.
  • Color change gems display different colors under varying light. Varieties include alexandrite, color-change sapphire, color-change garnet, diaspore and color-change fluorite.
  • The traditional engagement ring is diamond. But many couples are now selecting colored gemstone engagement rings. Here is what to look for in a fine colored gem for an engagement ring.
  • High quality gemstones show best when set in fine jewelry. Here are some examples of our fine gems set in custom jewelry designs.
  • Concave cutting is a recent innovations that creates 3 dimensional curved facets, enhancing a gemstone's brilliance.
  • Gemstones may be formed in single or multiple discrete crystals (such as diamond), in massive collections of microscopic crystals (such as chalcedony), or in amorphous (non-crystalline) masses (such as opal)
  • Cuprite is a copper oxide that is very rare in gem-quality. Virtually all of the gem cuprite in facetable sizes came from a single unique deposit in a copper mine in Onganja, Namibia.
  • The process of cutting and polishing gemstones is known as lapidary. It transforms rough minerals into brilliant and lustrous faceted gems.
  • Danburite is a natural gemstone that is valued for its excellent transparency and clarity, especially in white or colorless stones.
  • This month we cut the last of our rough stone from the original deposit of Mahenge spinel. This material is no longer available in the market. Own one of the rarest and most beautiful spinels ever discovered!
  • This month we feature a very rare 75 ct Yellow Star Sapphire from Ceylon. Also: Notable Gems, Gem News from around the world, and our gem experts answer your questions.
  • This month we feature fine matched pairs from our collection. Perfect for gifts!
  • This month we feature unique Gemstone Suites from our collection. These have been carefully matched by our staff and include earring sets, pendant/ring/earrings suites and some elaborate necklace layouts.
  • This month we feature fine Mineral Specimens from around the world. Fine uncut gem crystals are natural works of art and are sought after by collectors.
  • For gemstone connoisseurs and investors, Burmese ruby and jadeite are the ne plus ultra of colored gems. We are delighted that it is once again possible to ship these rare stones to collectors around the world.
  • Determining geographic origin by close examination of the gem material is a long standing goal of gemological science, and some gem labs now issue origin reports.
  • Diamond melee are very small diamonds, usually less than 0.18 carats. They are used in jewelry as accent stones or in closely packed clusters known as pave.
  • Electronic gem testers have become handy for checking diamonds, but these devices are not yet useful for identifying colored gemstones. Learn why.
  • Almost all emeralds are fracture-filled to improve their clarity. The use of polymers such as Opticon for clarity enhancement has changed the emerald market.
  • Traditionally the precious opal market has belonged to Australia, with more than 95% of the world's production. But recent finds of high quality opal in Ethiopia are transforming the opal business, much to the consternation of the Australians.
  • Most fine transparent gemstones in the market have been faceted -- fashioned with a series of flat planes known as facets. This is actually a recent innovation in the history of gemstones.
  • Tanzanite is most famous for its rich violet-blue color, but there are now a range of other colors being marketed as fancy color tanzanite. Some of these are quite rare and valuable.
  • This month we look at natural zircon, one of the the most brilliant but underappreciated species in the gems world.
  • This month our feature is on the Tucson Gem Show. Also: Notable Gems, Gem News from around the world, and our gem experts answer your questions.
  • This month we discuss one of the maxims of the colored gem trade -- "buy it while you can." Fine gems are in short supply and increasing demand from China has made it more difficult and expensive to acquire good stones.
  • This month we look at quality factors for appraising Tanzanite, the rare violet-blue form of the mineral zoisite.
  • There are certain rare tsavorite garnets that combine a medium tone with an intense saturation. Some of these so-called Mint Garnets are so remarkably vivid that they are as striking as any emerald.
  • Most amethyst gemst comes from South America. But some of the finest amethyst is found in Africa, especially in Zambia.
  • We specialize in one-of-a-kind gems with top color and excellent cut. Buy the best quality gemstones online from the internet's leading gems dealer.
  • We specialize in high quality, precision-cut natural gemstones. We offer the best prices in the market for top grade gems.
  • If you are looking for a fine pink gemstone in a very large size, kunzite may be just what you're looking for.
  • Spinel is a gemstone that is finally getting the recognition that it deserves. For a long time spinel had been confused with ruby and sapphire, two gems that it resembles in many ways. Among gem aficionadoes spinel is now one of the most sought after gems in the market, with red and pink the top colors.
  • Star rubies are about the rarest of the star gems. Fine specimens come from Burma, Sri Lanka, Mozambique and Vietnam.
  • Rare tsavorite garnet is challenging emerald as the finest of the green gemstones. Learn why tsavorite is special.
  • Fluorite is enormously popular with mineral collectors, and is also valued as a gemstone for its wide range of colors.
  • Many of our gems include certificates from independent gemological labs, such as GRS. But we offer optional certification for all our gems.
  • The rarest and most expensive material in the quartz family is a type of chalecedony known in the trade as "gem silica".
  • The gemstone trade depends on gemological laboratories with sophisticated equipment for gemstone identification. But you might be surprised to know that even the best gem labs can't tell you how much a gemstone is worth. To find out about the quality and value of a gemstone you need to turn to the people who make their living trading in gemstones -- gem dealers.
  • The terms brilliance and luster have specific technical meanings in the world of colored gems. The term brilliance in particular is often misunderstood.
  • At one time all gems were shaped as cabochons. Today most gems are faceted, but some are still cut as cabs, because they have special optical qualities or are too opaque to facet.
  • A gemstone may be a pure chemical element (diamond is essentially pure carbon), a relatively simple chemical compound (quartz is silicon dioxide, SiO2), or a more complex mixture of various compounds and elements (the garnet family includes a highly variable mix of iron, magnesium, aluminum, and calcium silicates).
  • The cleavage characteristics of a mineral are one of its identifying properties, and a factor that must be taken into account when cutting or setting a gemstone.
  • A chart of gem varieties organized by color -- red, blue, green, pink, yellow/gold/bronze, orange, violet/purple, white/colorless and multicolor.
  • The color of a gemstone varies with the illumination used to view it. This fact is particularly important for buying ruby and blue sapphire.
  • Gem materials vary greatly in density -- amber may float in salt water (density near that of water), while hematite is more than five times the density of water
  • The most complete and accurate density chart for gemstones available online, with specific gravity ratings for many rare varieties.
  • Which gems are strong enough to be set in a ring that will be worn every day? We provide some answers.
  • Browse the largest library of gemstone information on the internet, and subscribe to our monthly newsletter.
  • The term "fire" refers to the ability of a gem to split light into the colors of the spectrum. The term "scintillation" refers to flashes of light that are produced when a gem is moved in the light.
  • This is a glossary of technical terms commonly used in the gem and jewelry business.
  • The most complete and accurate hardness chart for gemstones available online, with hardness ratings for many rare varieties.
  • Rare gemstones from AJS Gems, Bangkok have been set in fine jewelry all over the world. This gallery shows some of the designs that were created by our customers using our gems, as well as some of our own designs.
  • The international standard for measuring gemstones is millimeters. If you're not familiar with the metric system, this conversion chart will help you understand gemstone sizes.
  • Does it matter that a ruby was mined in Burma rather than Madagascar? Learn why country of origin is so important in the gem world.
  • This gallery of fine gemstones displays large images of gems from the AJS collection, including many different shapes and cuts.
  • Accurate gemstone photos are essential for buying gems online. Learn how we take our gem photos.
  • The refractive index of a gemstone is an important characteristic which helps to determine the appearance of the gem. This property can easily be measured to help in identifying gemstones.
  • The most complete and accurate refractive index chart for gemstones available online, with refractive index ratings for many rare varieties.
  • A fine gemstone shows best when set in beautiful jewelry. When choosing a setting for your gemstone, there are a number of choices, including the type of metal, the ring design and the type of mounting.
  • All reputable gem dealers disclose gem treatments, and often provide test reports from gemological laboratories. But some gem enhancements are not detectable by even the best gem labs.
  • When you buy a diamond, every tiny imperfection in the stone lowers the clarity grading and thus the value. In the world of colored gemstones, some inclusions are expected and do not necessarily detract from the value of the gem. Indeed, in some cases distinctive inclusions actually make a stone more valuable.
  • One of the common cutting defects in colored gemstones is a phenomenon known as windowing. The term refers to an area of reduced color in the center of a stone, like looking through a glass window.
  • Astrology has allocated certain gemstones to each of the zodiac signs. In some cases, these coincide with the same stone as for the monthly birthstone charts, in others they differ. As with monthly birthstones, there are many differing opinions as to the appropriate gemstone for each sign.
  • There are three main components of color that affect gemstones: hue, saturation, and brightness. We need all three of these components to fully describe color.
  • Since the advent of the art of faceting gemstones in the 14th century, a number of different cutting styles have been produced by skilled lapidaries.
  • Gemstones vary by hardness and this fact is important both for mineral identification and for selecting gemstones for jewelry.
  • The term "shape" in the gemstone world usually refers to the outline shape of the gemstone, while the term "cut" refers to the faceting pattern.
  • Yellow or golden beryl is also known as heliodor or yellow emerald. It is an inexpensive gem that is popular as an alternative to the more expensive yellow sapphire.
  • Gem-quality grandidierite is extremely rare, and it often appears on the list of the 10 rarest varieties in the world, along with gems like jeremejevite, painite, benitoite and taafeite.
  • Green is an important color for garnet, but the green garnet varieties tend to be rare, such as tsavorite, demantoid and mali garnets.
  • Though green is the most typical color in tourmaline, the color variation is vast, ranging from sea green to apple green, mint green, forest green and avocado.
  • What are your choices in blue gems? Take a tour through the world of blue gemstones, including some rare varieties.
  • Bangkok is the gemstone capital of the world. To get the best prices on fine gems, you need to visit the wholesale dealers who supply the world's leading gem dealers and jewelers.
  • There is now a large and established online market for loose gemstones. But buying gems online still involves some risk, so here is some useful advice for careful buyers.
  • The most common gemstone fraud is not synthetic gems as natural, but rather the selling of low quality stones as fine gemstones, especially stones that are poorly cut, heavily included or of mediocre color.
  • What are your choices in green gemstones? Take a tour through the world of green gems, including some rare varieties.
  • What are your choices in orange gems? Take a tour through the world of orange gemstones, including some rare varieties.
  • Sapphire has become increasingly popular for engagement rings, especially for couples looking to buy a unique gem with vivid color, and in a larger size.
  • Natural zircon is a favorite of gem dealers and collectors, but it is not well known in the jewelry market. Learn about prices on fine natural zircon.
  • It is now possible to manufacture many kinds of gemstones in the laboratory, including sapphire, ruby, emerald and diamond. So what does this mean for the natural gemstone business? Why should a natural gemstone be preferred?
  • Some natural zircons have been damaged by self-radiation and are known as low zircons. Most of the zircons sold as gemstones are high zircons.
  • The idea of birthstones -- a gemstone assigned to each month of the year -- is thought to be an ancient one. But that is not really true. The birthstone concept as we know it actually dates approximately to 18th century Poland. And the modern list of birthstones was not defined until 1912.
  • A marquise cut gemstone is an elliptical shape with pointed ends. It is a long and elegant shape that makes the most of a gem's carat weight.
  • When buying a colored gemstone always check the size as well as the weight. Colored gems vary in density and cut, and one cannot accurately predict the size of the stone from the carat weight, as one can with diamonds.
  • Precious opal is one of the most unique gemstones in the world, but it is also one of the most fragile. Indeed it is fair to say that opal is one of the most delicate gems commonly worn. So if you own opal jewelry or are thinking about having opal set in a ring, pendant or earrings, this article will help you to keep your opal in good condition for years.
  • A Chelsea Filter is an inexpensive diagnostic tool that can be useful for identifying certain gemstones. But it is important to understand how the filter works so that you can also understand its limitations.
  • Idocrase is rarely found in gem quality and transparent material that can be faceted is especially rare.
  • Blue is the rarest tourmaline color. A pure blue is very rare and most indicolite is a teal or blue-green.
  • Hard assets are a sound investment. Fine gemstones are a tangible store of value in turbulent times.
  • Iolite is typically light to dark blue or violet blue in color, with excellent transparency and strong pleochroism.
  • Jade is actually 2 different minerals: nephrite and jadeite. Learn why jadeite is the more valuable form of jade.
  • This month we look at some of the colored gemstone jewelry from the Elizabeth Taylor collection that was recently auctioned at Christie's in New York.
  • This month we feature a rare 11 ct Star Spinel from Tanzania. Also: Notable Gems, Gem News from around the world, and our gem experts answer your questions.
  • This month we look at spessartite garnet from Nigeria, where fine material was discovered in 1999. Unfortunately the mine has now been worked out.
  • Cuprite is an unusual mineral with several interesting properties. Gem quality specimens are rare and of great interest to collectors. Some rare large gem-quality crystals have been found in Namibia.
  • Tanzanite is most famous for its rich violet-blue color, but there are now a range of other colors being marketed as fancy color tanzanite. Some of these are quite rare and valuable and thus popular with collectors.
  • Welcome to the new AJS Gems Newsletter! This month we're introducing a new monthly newsletter format, with more information about gemstones and the gem world.
  • This month's feature is on the rare Tsavorite Garnet from East Africa. Plus new additions to our extensive collection.
  • This month's feature is on The Enduring Pleasures of Ceylon Sapphire. See our latest acquistions and all the news from the gems world.
  • This month we look at the importance of fine cutting for colored gems. A fine cut is actually a high priority in colored gems, not least because it impacts color, and impacts other optical properties related to color, such as brilliance, luster and scintillation.
  • This month's feature is on Cobaltocalcite, a rare reddish-purple calcite colored by traces of cobalt. We have cut some beautiful pieces with vivid color and unusual translucency. GIA wrote an article on our Cobaltocalcite in the Spring 2015 edition of Gems & Gemology.
  • This month we feature the unusual Black Star Sapphires from Thailand. These unique gems have a golden star that can be seen under a focused light. Some rare specimens have a 12 ray star.
  • This month's feature is on Arnold's recent trip to Kenya and Tanzania. Plus the latest news on Burma sanctions and a new corundum find in Madagascar.
  • This month's feature is on Investing in Fine Gems. Also this month: notable gems from our collection; news from AJS and the gems world; and answers from our gem experts to customer questions.
  • This month we look at the rare Malaia Garnet, a hybrid of pyrope, almandite and spessartite.
  • Now you can view our website on your smartphone -- this month we introduce the mobile version of AJSgem.com. Browse fine gemstones wherever you happen to be.
  • One of the rarest -- and least known -- colors in tourmaline is a vivid yellow known in the trade as Canary Tourmaline.
  • The most valuable sapphires in the world are from Kashmir, but chances are you will never see one except at a rare gems auction or in a museum.
  • If you are new to gemstones, or just curious about all the different varieties available, this photographic index shows the astonishing diversity and striking beauty to be found in the gemstone world.
  • If you want a fine piece of colored gemstone jewelry, selecting a high quality loose gemstone first will get you the best choice and the best value. Learn where to buy the best gemstones online.
  • In a very short time, Madagascar has become one of the most important producers of high quality sapphire.
  • Citrine is the most popular gemstone in the yellow to orange color range, and one of the most affordable of the harder gem materials.The most valuable citrine is a saturated color known as Madeira Citrine.
  • A new find of neon pink-red spinel near Mahenge, Tanzania in 2007 produced the latest sensation in the world of rare gemstones.
  • Malaia Garnet is a hybrid pyrope-almandine-spessartite garnet found mainly in east Africa. Colors range from pinkish-orange to reddish-orange and cinammon.
  • Mali Garnet is a recently-discovered variety that is a hybrid of grossularite and andradite. It is a rare gem that is notable for its fire or dispersion.
  • This month we look at fine amethyst. Once a rare gem, top grade amethyst is still rare. Most of the world's amethyst supply comes from South America. But the finest amethyst comes from Africa, especially Zambia.
  • This month our feature is on the marvels of Pink Tourmaline. Also: Notable Gems, Gem News from around the world, and our gem experts answer your questions.
  • This month we look at the latest on gemstones prices from the recent Tucson gem show. Fine gems are in short supply and prices are up strongly on even fairly ordinary gems.
  • This month we look at the amazing variety of fine tourmaline coming from Africa, especially Nigeria, Mozambique and Tanzania.
  • This month we look at the fine chrysoprase from Australia, a rare apple-green quartz with very good translucency that produces a wonderful luminosity.
  • This month's feature is on the rare gem known as gem silica chrysocolla. We have been cutting some fine material from Arizona and Peru.
  • This month's feature is on the rare Imperial Topaz from Ouro Preto in Brazil. Also this month: notable gems from our collection; news from AJS and the gems world; and answers from our gem experts to customer questions.
  • This month we look at grading standards for Imperial Topaz, the rare golden-orange or pink-orange color of topaz.
  • This month we look at fine amethyst from the world's main 3 locations: Zambia, Uruguay and Brazil.
  • Gem Brazilianite is a rare collector's stone first discovered in 1944 in Brazil. It's an attractive gem with a vivid yellowish-green hue and excellent transparency and a vitreous luster.
  • Fire opal from Mexico is valued for its vivid body color, which ranges from white to yellow to orange-red.
  • Moonstone display the unique property of adularescence -- a shimmering light that appears to emanate from below the surface of the gem
  • Moonstone is notable for its adularesence -- a shimmering light that appears to emanate from within the stone. It is caused by a layered structure that scatters light.
  • The rare pink color of beryl is known as Morganite, named after the American financier and philanthropist, JP Morgan.
  • Mozambique has become an important producer of high quality ruby since the discovery of a significant deposit in Montepuez in 2009.
  • Most natural gemstones are a single color -- red or blue or yellow or green, and so on. But there are some rare gems which display multiple colors in a single stone, and these are of particular interest to gem lovers and collectors.
  • Alexandrite is the name used for the rare chrysoberyl that exhibits a distinctive color change. It is one of the rarest and most valuable of all colored gems.
  • The name ametrine is a combination of amethyst and citrine, the most well known forms of the mineral quartz. Ametrine combines the purple of amethyst and the golden yellow of citrine in the same gem.
  • Blue is the most popular color for natural zirocn and fine blue zircon has more sparkle than any other blue stone in the gemstone world.
  • Among the few gemstones that occur in a pure vivid green, chrome diopside is the most affordable. But since it is a slightly soft stone, it is not suitable for rings worn everyday.
  • Imperial topaz, also known as precious topaz, is the rarest color of topaz -- a golden-orange to pink hue. Fine specimens come from the Ouro Prêto region in Brazil.
  • The term Padparadscha refers to a rare orangey-pink or pinkish-orange color of sapphire.
  • Rubellite is the name used for the intense pinkish-red to violet-red tourmaline. It displays one of the most vivid colors of any gemstone variety.
  • Natural ruby is the rarest and most valuable of colored gems. Burma is the traditional source for fine ruby, but new material is mainly coming from Madagascar, Tanzania and Mozambique.
  • Though many gems are enhanced by treatments, it is still possible to buy fine untreated gems in today's market. There are some gem varieties which are rarely, if ever, treated.
  • The North American continent -- including Canada, the USA and Mexico -- is rich in minerals, including gemstones such as diamond, tourmaline, sunstone and gem silica.
  • This month we offer our advice on the best values in fine gemstones for the holiday season. Give that special someone in your life a meaningful gift of lasting value.
  • This month we offer our gift ideas for the holiday season. Also: Notable Gems, Gem News from around the world, and our gem experts answer your questions.
  • This month's feature is on Gems for Collectors. We supply rare stones to fine jewelers and collectors around the world.
  • This month we look at Diaspore, a rare color change gem from Turkey. Diaspore displays a subtle color change from a kiwi-like green in daylight to a champagne color in incandescent light, and a light purplish-pink under low intensity lighting such as candelight.
  • This month we feature exceptionally rare Grandidierite from Madagascar, one of the 10 rarest gem varieties in the world.
  • Green is the most typical color in tourmaline but there are some shades of green tourmaline which are quite uncommon and valuable. These include a a saturated chrome green, unusual bi-colors, rare teal or blue-green, and an intense neon green.
  • This month our feature article looks at gemstone trends based on our experience at the recent Hong Kong gem fair. The Asian market is driving gem prices higher and the investment community is starting to notice.
  • This month we report on the September Hong Kong Gem Fair. Also this month: Notable Gems, Gem news from around the world and our gem experts answer your questions.
  • This month we feature a very rare gem -- a 5.46 ct unheated ruby from Mogok, Burma with special certificates from GemResearch Swisslab and Gubelin Gemlab.
  • This month's feature is on Oregon Sunstone, the finest sunstone in the world. The finest specimens occur in vivid orange or red, with fine-grained copper inclusions that display a glitter or schiller.
  • This month we feature rare Sphalerite from Spain, a rare gemstone with a fire or dispersion rating higher than diamond. The finest Sphalerite comes from the Aliva mine in northern Spain.
  • The most valuable citrines are the natural gems in the saturated colors, known in the trade as Madeira Citrine. The name derives a fortified Portuguese wine made in the Madeira Islands. The color of Madeira ranges from golden to golden-orange to reddish-brown to brown.
  • Oregon sunstone is regarded as the finest sunstone in the world, and the only sunstone with copper inclusions.
  • Most gemstones are minerals, but some are not. Learn about the fascinating organic and non-crystalline gemstones.
  • Peridot is one of the more unusual stones in the gems world, with unique geological and gemological properties.
  • Natural pink sapphire is a rare gemstone that is popular for fine jewelry and sought after by gem collectors.
  • Pink is the rarest color in tanzanite, and high quality specimens and polished gems are sought after by collectors.
  • For lovers of pink gems, there is no gemstone variety which provides as many choices as pink tourmaline.
  • White gold and platinum are now the most popular precious metals for jewelry. Learn about the differences between these two metals.
  • One of the most familiar distinctions in the gems world is that between precious and semi-precious gems. But while you'll often hear these terms, they are now officially discouraged in the gemstone business.
  • The most important features of colored gems are color and clarity. Cut is relevant as it enhances those features. Poor cutting is usually the result of trying to maximize carat weight.
  • Prices for colored gemstones can confuse even experienced buyers. Learn how gem dealers price their gems for the market. The price you pay for a gem should be a function of quality and rarity of the stone you are buying.
  • Although many people are content to collect gemstones, most gem lovers like to have their gems set in jewelry so they can be worn. Unfortunately, despite their reputation, gemstones are not necessarily forever and do need care. Most people are not sure how to care for their fine gemstones. Here you'll find a few tips.
  • Pukhraj is the Hindi name for yellow sapphire. Yellow sapphire has a special significance in Vedic astrology, where there are 9 gems thought to correspond to the 9 planets: ruby, pearl, coral, emerald, yellow sapphire, diamond, blue sapphire, chrysoberyl cat's eye, and hessonite garnet. Yellow sapphire is associated with Guru or Jupiter, the largest planet in the solar system.
  • The garnet family is not confined to the common dark red garnets. There are rare garnets such spessartite, tsavorite, demantoid, rhodolite and color-change. They are among the finest of colored gemstones.
  • Cobaltocalcite is a rare calcite colored by traces of cobalt. Especially fine material has a vivid reddish-purple color and excellent translucency.
  • We supply rare gemstones to fine jewelers and collectors around the world, including Burma ruby, Ceylon sapphire and the finest spinel, topaz and garnet.
  • Rare gemstones tend to appreciate in value over time. With limited supply and increasing demand, we have entered a period of rapidly rising prices for the best colored stones.
  • A rare transparent green oligoclase has been found in east Africa and Vietnam. This rare feldspar is of interest to gem collectors.
  • Jeremejevite is a rare aluminum borate mineral that sometimes occurs in a gem-quality clear crystal form. It is generally classified as one of the rarest gemstones in the world, along with such rare stones as painite, taaffeite and poudrettaite.
  • Kornerupine is a rare boro-silicate mineral that is especially rare in gem quality. High quality specimens are popular with collectors.
  • Colorless garnet is known as leuco garnet. It is very rare, and high quality specimens are prized by gem collectors.
  • All natural pearls are rare, but there are some especially rare varieties which are treasured by collectors. They include the beautiful Melo pearl found in waters in Southeast Asia.
  • It is a rare event in the gemstone world when a new gemstone variety is discovered. One of the most recent discoveries is an intriguing and beautiful mineral known as Pezzottaite, first discovered in Madagascar around 2002.
  • Serendibite is a rare borosilicate mineral that is very rare in gem quality. A recent find in Mogok, Burma has made this rare stone available to collectors.
  • Taaffeite is a very rare gem variety and is often included in the list of rarest gemstones in the world.
  • Williamsite is a rare translucent to transparent member of the serpentine group and is valued for its jade-like color.
  • All gemstones are rare, since they constitute a tiny percentage of the minerals found on earth. But some gemstones varieties are extremely rare, insofar as only a small number of gem-quality specimens are known to exist.
  • Rhodolite is the finest of the red garnets, with a color that ranges from rose to raspberry, without a trace of the brown secondary hue found in the common garnets.
  • Here are some gemstone reference works that we have found particularly useful.
  • Rhodochrosite is a manganese carbonate, usually red or pink in color. The finest examples come from the Sweet Home Mine in Colorado.
  • We specialize in the finest cut and polished gems, and occasionally offer high quality rough stone, mineral samples and gem carvings as well.
  • Fracture-filling for ruby is not a stable treatment, and consumers should avoid these low quality stones.
  • The rarest and most valuable demantoid garnet comes from Russia. It displays unique horsetail inclusions not found in gems from other locations.
  • In the gem trade, the term "sapphire" traditionally denotes blue sapphire, where all other colors of sapphire are referred to under the label "fancy sapphire." But while blue is still the classic color for sapphire, many other sapphire colors have become popular, including violet, pink, yellow, white, orange and green.
  • Sapphire and ruby are the most colored stones for special occasion jewelry, due to their vivid color, rarity and excellent hardness.
  • Scapolite is one of the lesser known gemstones, though of considerable interest to the collector or student of gemstones.
  • This month our feature article takes an inside look at the colored gemstone business. Learn why it's so difficult (and expensive) to buy finer colored stones from retail jewelers.
  • This month our feature article is on sphene, a rare gem with more fire than diamond. Also this month: notable gems from our collection; new gem videos; gem news; and our gem experts answer your questions.
  • This month's feature is on the U.S. ban on Burma ruby and jadeite. See our latest acquistions, read all the news from the gems world and get answers to your questions from our gem experts.
  • This month's feature is on the rare Color Change Garnet from Bekily, Madagascar. It is the only deposit of blue garnet in the world.
  • This month we feature some of the rarest natural pearls in the world -- the Melo Pearls from Burma. These beautiful large pearls occur in a vivid orange color with a porcelain luster. Particularly fine specimens display a delicate flame-like structure.
  • Tanzanite, discovered in 1967 in East Africa, is one of the great success stories in the gem world, and is one of the best values in colored gemstones.
  • If you want a fine piece of jewelry, select a high quality loose gemstone and work with a custom jeweler to create your own design. Here are some setting ideas for different shapes.
  • The main sources for gem silica chrysocolla are the Inspiration and Ray Mines in Arizona and the Lily Mine in Peru.
  • Spessartite or mandarin garnet is one of the finest of all colored gems, with excellent brilliance and sparkle.
  • Sphalerite is a collector's gem famed for its remarkable fire or dispersion. The finest sphalerite comes from the Aliva mine in northern Spain.
  • Sphene is a rare collector's gem that is valued for its exceptional brilliance and fire. The best specimens currently come from Madagascar.
  • Spinel has long been a favorite of gem dealers, but in recent years it has become very popular with gem collectors and jewelry lovers as well. Learn about prices on fine natural spinel.
  • Natural spinel is one of the rarest and most beautiful gems in the world. It is an ideal gem for fine jewelry, including rings, pendants and earrings.
  • Natural gemstones that display a star -- a phenomenon known as asterism -- are rare and have long been valued by collectors. The most notable star gemstones are star sapphire and star ruby, though asterism can occasionally be found in other gem varieties as well.
  • What makes top grade tanzanite so valuable? We look at tanzanite grading and the determinants of tanzanite value.
  • Learn about this history of Tanzanite prices and how top grade Tanzanite is priced in today's market.
  • Thailand is the source of many of the world's finest colored gemstones, and Bangkok is the capital of the international gem and jewelry trade.
  • Thailand is facing the worst flooding in more than 50 years. Now the city of Bangkok waits anxiously for the flood waters to arrive ...
  • The US has banned the import of Burmese gems, especially ruby and jadeite, since 2003. The ban has still not been lifted. Read about the latest developments.
  • Fine gemstones are a reliable store of value that is compact, portable and private. Learn about the top 10 investments in colored gemstones.
  • The term top grade refers to gems of of lasting value that are of interest to collectors and investors. See our collection of top grade gems.
  • See our large selection of high quality tourmaline in all the colors of the rainbow. Buy fine tourmaline from the gem experts at AJS Gems, Bangkok.
  • Tourmaline is valued for its incredible range of colors and its vitreous luster. Learn about prices on fine tourmaline varieties.
  • The term trillion or trilliant is used to describe a gemstone cut that is triangular in shape. Trillions can display impressive brilliance and sparkle.
  • Learn about the types of jade, the most valuable colors and the standards used to grade it.
  • Umbalite Garnet is a high quality rhodolite garnet from the Umba River region of Tanzania. The color is a bright pink-red or purplish-red.
  • Gemstone hardness is rated on the Mohs scale. But this scale doesn't tell us everything we want to know about the durability of a gem.
  • The expression "natural sapphire" is used a good deal these days in the gem and jewelry business. But it is a term that can easily mislead or confuse consumers. So it is worth considering what it means for a sapphire to be natural, and why consumers are concerned about the sapphires in the market.
  • There are very few gems which display different color regions in the same gemstone. Ametrine quartz, which combines the colors of amethyst (purple) and citrine (gold), is a rare example. This is a property especially associated with tourmaline, where bi-color and tri-color stones are relatively common.
  • See the complete list of gemstones assigned to the different anniversary years.
  • Goshenite or white beryl is a natural gemstone that is valued for its excellent transparency and clarity. It is one of several natural alternatives to diamond.
  • Looking for a fine colorless gemstone, but don't want to buy a high price for a tiny diamond? There are a number of choices in fine white precious and semi-precious gemstones, including some lesser known gems. These include sapphire, zircon, topaz, rock crystal, goshenite, danburite and petalite.
  • Zircon is a gemstone that is a favorite of gemologists and geologists. Zircon is famous for its brilliance and fire, but it also has some some unusual properties.
 
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