Thanks to Chuck Fipke, the entire mining industry, along with most other Canadians, realize that there are mineral commodities aside from metals worth exploring for. Whereas only a handful of companies were historically involved in diamond exploration, dominated by the ever-secretive De Beers, today there are literally hundreds of companies involved in the global pursuit of “a girl’s best friend,” an activity considered to be well within the mainstream of the global mining industry.
Meanwhile, Canada is well on its way to becoming one of the world’s leading diamond producers, contributing thousands of jobs and hundreds of millions of dollars to the Canadian economy in the process, not to mention the benefits derived by those who invested in the companies that found these deposits to begin with.
Not far behind, and to a certain extent as a result, investors and companies are also beginning to realize that there are many other valuable gemstone commodities worth exploring for, besides diamonds. Collectively, these are known as “semi-precious” or “coloured” gemstones, and they comprise everything from chalcedony to corundum, or, as they would be known in the gemstone trade, from sard to sapphire. Ever since man first blinked out from his smoky cave over the great beyond, coloured gemstones have been one of the most consistent, and consistently profitable, pursuits of man. From lapis lazuli inlay in the mask of Tutankhamen, to the rubies and emeralds in the British crown jewels (in Buckingham Palace or wherever the old gal is hiding them, long may she reign!), coloured gemstones have, since time immemorial, occupied a prominent place in human society as objects of prized and valuable possession.
In the past, people generally referred to all gemstones aside from diamonds as “semi-precious,” but this term has been discarded in favour of “coloured,” mainly because the finer grades of a large variety of mineral species, even down to the more mundane minerals such as certain varieties of garnet, can attain values approaching those of diamonds (which comprise a wide range of value themselves). Some, such as the rare gemstone alexandrite, a variety of the mineral chrysoberyl, may attain values in excess of US$6,000 per carat, surpassing that of all but the finest diamonds (recall that a carat is only one-fifth of a gram!).
So what is a gemstone anyway? Gemologists (people who are trained in a variety of mostly optical, non-destructive tests to identify and valuate both rough and faceted gemstone minerals) apply three basic criteria to determine if a material is a gemstone: beauty, rarity and durability. By this definition, any of the rare and beautiful varieties of feldspar are considered gemstones, as indeed they are, whereas dark brown to industrial diamonds are not. This definition includes both the organic and inorganic products of nature, such as coral, ivory (currently banned in most of the “civilized” world), and jet (a variety of coal). Strictly speaking, this definition excludes materials that are not products of nature or that have been altered in any way by human influence so as to improve their appearance, unless the treatment is clearly disclosed and the gemstone is identified accordingly (“heat-treated sapphire.” for example).
Unfortunately, such distinctions are rarely made, and in many cases the sales staff at the jewelry store may not even know. This subject represents an entire branch of gemology in its own right — one which is too lengthy and complex to elaborate on here but which includes:
— synthetic gemstones (same composition but man-made);
— imitation gemstones (different composition but similar in appearance);
— treatments (heating, oiling, irradiating, coating, etc.);
— doublets (a thin slice of the real thing on top of something much less valuable);
— triplets, etc., etc.
Advances in technology continue to make such subterfuge more and more difficult to detect. Large laboratories all around the world, full of sophisticated and expensive equipment, are employed full time in this pursuit. And like the arms race, as soon as a method is found to detect a particular treatment process or new synthetic, somebody comes along with a new one that is undetectable (including diamonds). This problem is a matter of ongoing debate and increasing regulation in gemological circles but will never be completely overcome. This is one reason we have gemologists!
To confuse things further, unlike most mineral commodities (with the exception of facing stone), gemstones may have trade names that have nothing to do with their actual mineralogical composition. For example, the generally grey-blue variety of zoisite that turns a bright bluish-purple upon heating is commercially known as “tanzanite” since it has so far been found only in Tanzania. Likewise, the emerald-green variety of grossular garnet first found near the Tsavo River, in Kenya, is known as “tsavorite.” Sometimes, these names are intentionally conceived to convey an inflated sense of value, such as “water sapphire” (also known as “iolite”), the gem variety of the mineral cordierite, or “Herkimer diamond,” a particularly clear, well-crystallized variety of quartz found near Herkimer, N.Y. This practice is generally frowned upon by gemological and jewelry trade associations but remains widespread nonetheless.
However, for those engaged in the exploration and development of authentic, God-created coloured gemstones, this is not a concern. Similar to all concentrations of specific minerals — things we call “mineral deposits” and (if it looks like we can extract them at a profit) “mines” — gemstone deposits occur in specific geologic settings. Almost all countries host gemstone deposits of one sort or another, but certain countries are renown for their coloured gemstone endowment, among them Myanmar, Sri Lanka, Kenya, Tanzania, Mozambique and Madagascar, Russia, India, Colombia and Brazil.
In most of these countries, you will find Canadian mining companies engaged in the exploration for, and development/production of, various coloured gemstone deposits. In upcoming articles, I will review the major groups of coloured gemstones, where they are found, what they can be worth, and which mining companies are exploring for and developing them. So all companies out there that are involved with coloured gemstones, please make sure to send me an e-mail so I don’t overlook you. The address is avromeric.howard@utoronto.ca.
— Avrom E. Howard, M.Sc, P.Geo, FGA, is a professional geoscientist and certified gemologist. He is active in all kinds of mineral exploration, including metals, diamonds and coloured gemstones.
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