In our newsletter this month:

   The Science of Gemology
   New in Gems
   Staff Selections
   Gemstones Worth Knowing
   Customer Questions

Doing business in a product as rare and valuable as gemstones requires considerable honesty and trust between business partners. We put a lot of trust in our suppliers, just as our customers put a lot of trust in us. But the world being what it is, trust alone is not always enough. It also helps to know what you're doing.

The systematic study of gemstones has come a long way since the days when any attractive red stone was called a ruby. Today gemologists have to be able to identify over 200 different varieties of gemstones, as well as detect an ever-growing list of gem treatments and synthetics. What once was an art has become a science.

Every type of gemstone has a unique set of physical and optical properties. These include hardness, specific gravity or density, and refractive index. Though several type of gemstones may have approximately the same specific gravity or the same specific refractive index, each gem type has a unique profile when results of all the basic tests are considered. Just don't try to identify a gem by refractive index alone! You could easily be wrong.

The basic gemological tools are not difficult to learn to use. They include the simple 10x loupe (a powerful tool in the hands of an expert), the refractometer (for measuring refractive index), the polariscope (for identifying singly and doubly refractive gems), and a scale accurate to the 1/100th of a carat (for measuring specific gravity).

The binocular microscope is an increasingly important tool. It can be used reliably to detect signs of heat treatment or fracture filling, for example, though considerable skill and experience is required. Some forms of treatment can only be detected by specialized and expensive equipment. Detecting radiation treatment requires use of gamma ray spectroscopy, and beryllium treatment of sapphire is most reliably detected with a procedure known as LIBS (Laser Induced Breakdown Spectroscopy). You're unlikely to find these tools at your neighborhood gemologist.

A well-trained gemologist with vast experience in a particular kind of gem can often provide very detailed information about a gemstone, including information about its specific origin. But this sort of informed judgement about origin needs to be distinguished from the quantitative tests that yield definitive conclusions about the type of gemstone. This is usually reflected in the certificates issued by gemology labs. While the lab can conclusively identify the material as ruby (corundum); it can say only that the observed characteristics are consistent with the material being mined in Madagascar. Gemology has become a science, but there's still some art left in it.

Our buyers are in the market every day finding the best values for our customers. Here are some of the excellent buys we've made in the last few weeks:

• London Blue Topaz from Brazil: We have been finding some very fine topaz in the market in the highly regarded darker blue known as London Blue. A wide variety of shapes and sizes, including some superb matching pairs. Excellent hardness (8 on the Mohs scale) at an exceptionally good price.
  
  
• Emerald Pairs from Columbia: We've added some very nice matching pairs of Columbian emeralds. In sizes between 1.3 and 2 carats, these have excellent color and the pairs are very well matched (not an easy thing to do with emeralds). We think the price is extremely good as well.
  
  
• Yellow Golden Sapphire from Thailand: There has been some very fine yellow golden sapphire in the market here recently and we have been buying all we can find. These are very good sized pieces, mainly between 2 and 3.5 carats, with excellent luster and brilliance. They quite clean, with many graded VVS-VS.
  
  
• Tourmaline from Mozambique and Nigeria: We have been adding steadily to our stellar collection of African tourmaline, including an outstanding selection of pieces between 2 and 5 carats. These are ideally sized for rings, and the color selection and quality is really quite amazing.
  
  
• Kyanite from Cambodia: We've just received a new stock of Cambodian kyanite. These are lovely blue cabochons, mainly in the 2 to 4 carat size. An inexpensive gem with a unique color.
  
  
• Fire Opal from Mexico: We have been buying some wonderful Mexican fire opal, including a number of pieces in the rare mandarin or red-orange hue. We have a nice range of shapes and sizes available as well. If you're not acquainted with fire opal, this is a very attractive but inexpensive gem.
  
  
• Iolite from Madagascar: It has been a very long time since we came across fine Iolite, a a gem variety of the mineral cordierite. Iolite has a lovely violet blue hue and very good hardness (7 to 7.5 on the Mohs scale). We just found some very nice pieces, mainly in 1 to 2 carat sizes, with excellent color and clarity.
  
  
• Prehnite from South Africa: We had a good stock of prehnite last year and it sold out quickly. We've finally found some more in the market. These are superb cabochons in various shades of lime green.
  
  
• Amethyst from Brazil: We've been finding some very good buys in Brazilian amethyst recently, including some terrific matching pairs in larger sizes (up to 9 carats per pair). We also have a nice selection of cabochons in addition to our many faceted pieces.
  
  
• Yellow Golden Citrine from Brazil: We've just bought some new stock in fine Brazilian citrine, mainly trillion cut in sizes between 3 and 6 carats. Very good color and excellent Portuguese cut on these.
  
  
• Top Grade Spinel from Tanzania: We've recently found some of the finest spinel we have ever offered at GemSelect. We've bought a wonderful range of really outstanding colors, especially violet, blue and pink. And there are some very well cut pieces in larger sizes (2-4 carats). You'll also find some amazing electric pink red pieces that are really spectacular.
  
  
• Tsavorite Garnet from Tanzania: We've just purchased a small number of very high grade tsavorite garnet from Tanzania. Tsavorite, like emerald, typically has some inclusions. But these pieces are exceptionally clean, and they have a brilliance and sparkle that ordinary tsavorite just can't match. You'll find pieces in light green and forest green, mainly in sizes between 2 and 3 carats. We do have a few very special pieces in the 3 and 4 carat size, and one extraordinary gem at over 9 carats!
  
  
• Rhodolite Garnet from Tanzania: We have cut a number of pieces of a very high grade pinkish red rhodolite garnet from Tanzania. These have the pinkish-purple-red that is the most coveted color in rhodolite, with excellent clarity and luster. All the pieces are impressively large, with several pieces over 10 carats.
  
  

Each month our staff selects some of their favorite gemstones from our inventory. This month we feature a trio of stunning pieces from our recent acquisitions. Click on the photos to go to the detail pages.

Each month we focus on one of the lesser known gemstones. This month's featured stone is Moonstone.

Moonstone owes its name to its white, almost magical, shimmer that resembles moonshine. Blue-whitish light glides over the surface when the stone is cut en cabochon. Gemologists call this phenomena adularescence, which originates from the interior structure of the stone in scales or lamellas. Incoming rays of light are refracted inside the stone and scattered, creating a unique play of light.

Moonstone is the most well known variety of orthoclase feldspar. Specimens from Sri Lanka shimmer pale blue on an almost transparent ground. Moonstone from India typically show cloudlike plays of light and shade on beige brown, green or orange background. Star Moonstone is another excellent variety of moonstone. It comes in honey-colored, peach and green and exhibits a stunning cat's eye or four-rayed star effect together with its mystical sheen and glow. Star moonstones are rare, but we usually maintain a small inventory at GemSelect.

Moonstone is fairly soft (6 to 6.5 on the Mohs scale) so is not usually used in rings. But it can often be found in large sizes so it makes fascinating pendants. Moonstone comes from Sri Lanka, India, Madagascar, Burma, Tanzania and the USA.

For more information see our Moonstone Info Page.

Every month we answer questions of general interest from our customers. Please feel free to send your questions to help@gemselect.com, with "Newsletter question" in the Subject line. This month we have some questions about gem treatments.

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