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March 2008
 In our newsletter this month:
Tanzanian Zircon
New and Interesting Gemstones
New Content at GemSelect
Gemstones Worth Knowing
Customer Questions
Tanzanian Zircon
We wrote a newsletter feature on zircon two months ago and didn't expect to be writing about it again so soon. But we were so impressed by the Tanzanian zircon that has recently come on the market that we wanted to share the story of these exceptional gemstones.
 We know that many gemstone buyers are well acquainted with the attractions of zircon. We also know that some people have never heard of it, or confuse it with the diamond simulant cubic zirconia. Zircon is a zirconium silicate and is the oldest known mineral on earth. It has good hardness (6.5 to 7.5 on the Mohs scale) and it combines a very high refractive index (approaching that of diamond) with strong dispersion, the tendency to split white light into the colors of the spectrum. In short, zircon is a very brilliant gem with impressive fire.
Most of the zircon we've seen in the past comes from Cambodia, our neighbor to the east. Northwestern Cambodia produces very fine material, some of which can be heat-treated to produce the highly regarded blue zircon. But zircon in its natural state ranges in color from yellow-brown to orange and red.
The natural zircon colors have never had quite the same appeal in the market as the heat-treated blue. But we think that the impressive material recently found in Tanzania will change a lot of minds about natural zircon. The range of colors is unusual, with some stunning colors we've never seen before in zircon. And the clarity is outstanding, with virtually all the pieces VS grade or better, with more than half the stock VVS grade. But the remarkable thing is that these zircons are big as well!
 The colors include a range of oranges from golden brown to a spessartite-like mandarin. The most unusual colors are a range of rose tones, from cinammon to a pink cranberry, with some a combination of orange and rose hues. There are a few quite rare reds, from orange-red to crimson. The only heat-treated pieces in the group are some brilliant yellows; all the others are completely untreated.
There is a good selection of shapes, including ovals, rounds, pears, emerald cut and a few trillions and fancy cut pieces. Zircon is not a gem typically found in large sizes, but most of the pieces in this lot are over 2 carats. There are a good number of stones in the 5 carat size, with a few pieces as large as 6.9 carats. It is very unusual to find outstanding colors with great clarity in these large sizes.
We are buying as much of the Tanzanian zircon as we can. Right now the supply is good, but like many colored gems, one never knows how long it will last. The first signs of tightening supply is when the pieces get smaller and the clarity declines. So far we're still seeing large high quality specimens. |
| New and Interesting Gems -- updated November 9th |
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Watermelon Tourmaline from Nigeria: Watermelon tourmaline is one of the most distinctive gems in the world. We have just purchased a small number of exquisite pieces from Nigerian with outstanding color and clarity. These are the finest we've seen this year. |
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Boulder Opal from Australia: Boulder Opal is the second most prized form of opal, after black opal. The name derives from the fact that this opal is found embedded in ironstone boulders. Boulder opal is especially attractive because, like the black opal, it has a dark body tone which adds vibrancy to the play of color. We've just purchased a small lot of excellent pieces, in sizes between 4 and 15 carats. |
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Clinohumite from Tanzania: Clinohumite is a rare mineral. It is a member of the humite group of minerals, which includes humite, clinohumite, chondrodite, and norbergite. Only three sources of gem-quality clinohumite are known: the Pamir Mountains of Tajikistan, the Taymyr region of northern Siberia and the Mahenge plateau of Tanzania. Usually clinohumite is found in sizes under 1 carat but we just have acquired a small number of new pieces from Tajikistan in the 2-3 carat size. |
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Huge Topaz from Brazil: Gem-quality minerals are sometimes found in exceptionally large sizes. We've acquired some natural topaz from Brazil in sizes between 360 and 507 carats. We currently have 4 pieces in a light champagne color with outstanding clarity (all of been graded IF). Collectors take note. |
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Fluorite from Namibia: Fluorite is said to be the most colorful mineral in the world. We've just bought a new stock of some very colorful pieces, including electric greens and blues and some fascinating multicolor pieces. Most of the new pieces are in the 10 to 45 carat size, with a few larger stones, all with excellent clarity. We've recently added some very colorful cabochons as well. |
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Color-Change Diaspore from Turkey: Diaspore, sometimes marketed under the name Zultanite, is a color change gem from Turkey recently introduced to the international market. Under natural or fluorescent light, Diapsore has a kiwi green color, with flashes of yellow. Diaspore displays a champagne color under incandescent lighting, and when exposed to subdued lighting, such as candlelight, has a pinkish hue. We've recently bought a substantial number of new pieces, with a good choice of cuts and sizes. |
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Snowflake Obsidian from Mexico: Obsidian is a naturally occurring volcanic glass. It is formed when felsic lava extruded from a volcano cools without crystal growth.In some stones, the inclusion of small, white, radially clustered crystals of cristobalite in the black glass produce a blotchy or snowflake pattern, and this is known in the gem trade as snowflake obsidian. |
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Unheated Sapphire from Tanzania, Madagascar and Thailand: Our unheated sapphires have been very popular and we continue to increase our stock (now over 700 pieces). For the discriminating gem buyer who will accept nothing less than 100% natural, you'll find pink, blue, green, yellow and violet pieces, all guaranteed to be unheated. You may be surprised how affordable these are in the smaller sizes. |
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Seraphinite from Russia: Seraphinite is a trade name for a particular form of clinochlore, a member of the chlorite group. The dark green color of seraphinite is enhanced by a silvery and feathery shimmer caused by mica inclusions. Seraphinite was named for the seraphim, the highest order of angels, because of the feather-like appearance of the chatoyant fibers in the stone. This fascinating gemstone is a new addition our inventory. |
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Top Grade Amethyst from Brazil: We've just acquired some top grade natural amethyst from Brazil in very large sizes, ranging from about 20 to 75 carats. These are all VVS or IF clarity in the richest purple we've seen in amethyst in a long time. If you've been looking for a very special piece of amethyst, you'll want to check these out. |
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Demantoid Garnet from Namibia: Demantoid is the rarest and most valuable of the garnets, and is one of the most difficult to find of all colored gems. It is one of the few colored gemstones with a luster and brilliance similar to diamond. We have built up a stock of more than 100 pieces of Namibian demantoid, including some very fine matched pairs. |
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Amber from Poland: Amber is the fossilized hardened resin of the pine tree, Pinus succinifera, formed mainly in the Eocene epoch of the Tertiary period, about 50 million years ago. Amber has been used since prehistoric times for jewelry, amulets and religious objects. The most prized pieces contain inclusions of insects or plants or pyrites. Most amber is found in the Baltic region. We buy amber just a few times a year from our source in Poland and we've just added a new stock. |
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Turquoise from Afghanistan: Turquoise has been known and valued for thousands of years. We've bought some new pieces from Afghanistan, in an interesting variety of blue and blue-green hues. We've also found some of the popular apple-green turquoise that we first carried last year, and some superb matched pairs in blue. |
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Huge Star Rose Quartz from South Africa: We carry many large gemstones, but none as large as these Star Rose Quartz. We've collected 9 pieces over 100 carats, with the largest weighing in at an amazing 974 carats. The star effect in rose quartz is unusual in any size, but quite rare in these very large stones. |
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Axinite from Tanzania: Axinite is a group of brown to violet-brown or reddish brown minerals that sometimes occur in gem quality. Axinite is distinctive for its strong vitreous luster when polished, and its interesting pyro- and piezo-electric properties. Axinite is also popular with mineral collectors due to its unusual crystal structure. We have found a small stock of golden brown Axinite from Tanzania. |
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Spinel from Burma: We buy fine spinel whenever we can find it, and we've recently added some very fine pieces of Burmese spinel. You'll find red, violet, orange, blue and gray in a variety of shapes and sizes, including a good selection of pairs and lots. |
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Blue Sapphire from Madagascar, Ceylon and Tanzania: One of the most classic of all colored gemstones, the blue sapphire is always fashionable. This brilliant and hard-wearing gemstone is perfect for any kind of jewelry. We've added many new stones to our stock of more than 400 blue sapphires, including a number of excellent cornflower blue pieces. |
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Jadeite from Burma: Jade has been known and treasured for more than 7,000 years. But only in 1863 was it discovered that jade is actually not a single mineral. What was traditionally called jade is in fact two separate and distinct minerals: jadeite and nephrite. Jadeite is the rarer and more valuable jade, with the most famous deposits coming from Burma. We have verified samples of our Jadeite at the AIGS gemological lab in Bangkok. You'll find a good range of colors in these, including white, green and lavender. |
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Spessartite Garnet from Mozambique: We have added a large number of new pieces to our extensive inventory of this very popular gem. We now have over 500 pieces in stock, in mandarin and red-orange, in both cabochon and faceted. The range of sizes and quality grades is extensive. Our most recent additions are in the best mandarin orange color, mainly in smaller sizes. |
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Color-Change Garnet from Tanzania and Madagascar: We've recently found some rare Color-Change Garnet from Tanzania with a dramatic color change from greenish-brown to red pink. We have a small number of pieces, mostly eye-clean, in the 1 to 2 carat size. We've added these to our substantial stock of Color-Change Garnet from Madagascar. |
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Sphene from Sri Lanka: We have added some excellent new pieces to our stock of this rare gemstone famous for its remarkable dispersion or fire. These are bright golden and green pieces in interesting shapes and cuts, including a number of rounds in smaller sizes. Sphene tends to have inclusions, but we've found a number of eye-clean pieces. |
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Emerald from Colombia: We have just received a new stock of Colombian emeralds with rich color and good transparency. These are mainly ovals and pears in smaller sizes, ideal for earrings and ring settings. |
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New Content at GemSelect
We add hundreds of new gems to our inventory every day. But we also add new content to our site each week as well, in the form of articles and reference material.
We've recently written an article explaining gemstone cleavage, and we've put together a chart listing the cleavage properties for more than 60 varieties of gemstones.
In our growing Gemstone Articles section you'll find a number of new pieces on gemstones written by the GemSelect staff, on topics as diverse as gem appraisals and copper-bearing gems.
Gemstones Worth Knowing
Each month we focus on one of the lesser known gemstones. This month's featured stone is Beryl.
The beryl family is one of the most important gemstone families. It includes emerald, aquamarine and morganite as well as golden and red beryl. Beryl is quite a hard stone (7.5 to 8 on the Mohs scale) and suitable for all kinds of jewelry. Golden beryl, occurring in lemon-yellow and golden-yellow, tends to have exceptionally good clarity. Inclusions are rare in golden beryl, and the superb clarity combined with the fine color make this beryl an excellent stone for all kinds of jewelry. Golden beryl is found in Brazil, Madagascar, Namibia, Nigeria, Sri Lanka and Zimbabwe.
For more information see our Beryl information page
Customer Questions
Every month we answer questions of general interest from our customers. Please feel free to send your questions to help@gemselect.com. |
| Q: |
I notice that you sell red sapphire on your website. I thought red corundum is ruby while all the other colors of corundum are called sapphire. Am I right? AJB, USA |
| A: |
Yes, you're right. If it's red and it's corundum, it is almost always called ruby. There are really only a few exceptions to the rule. One exception is corundum that is red-orange or pink-red. It might be called either sapphire or ruby (it's a judgement call). The other exception is when the red color of the corundum is the result of heat treatment with beryllium. In that case it is normally called sapphire as a reference to its humbler beginnings.
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| Q: |
I bought 2 gems from you recently, but I forgot to print out all the details on them. Now I can't find them on your website. Can you help? MD, Australia |
| A: |
When a gem is sold, we no longer show it on our website, since no one wants to shop for items that aren't available. However, the information for sold items can still be found. Just enter one or more gem ID's (separated by commas) in the search box on our home page, and it will bring up the records for those gems. The gem ID is the 5 or 6 digit number that you'll find on every detail page, where you see a line that looks like "4.52ct VVS Tourmaline (#153854)." In that case 153854 is the gem ID. We always include the gem ID's in any emails we send you about your purchase. |
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| A final note -- If you send us email, please be assured that we answer all our email very promptly, 6 days a week. But we sometimes have problems with spam filters on the receiving end, so please adjust the settings on your mail client so you can receive mail from help@gemselect.com.
Happy gem hunting,
Your friends at GemSelect |
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