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Home Precious stones Rare Jewelry Stones

Rare Jewelry Stones

kamniPrecious stones such as sapphire, ruby, emerald, topaz, amethyst, aquamarine, turquoise, and others are known to virtually everybody. At the same time, not that many people heard of such wonderful gems as demantoid, heliodor, elbaite, spinel, alexandrite, hyacinth, or jadeite.

Also, there are stones that are still practically unknown, though they are very beautiful. In the whole world, only up to a dozen of professionals may know about them, but why is this so? Sometimes a beautiful stone is just too delicate; a piece with such stone can be exhibited in a museum but is unsuitable for wear. Other gems are simply dangerous to your health. But there are some unknown stones that are more than fit for jewelry business. But why are they still in the shadow of their luckier counterparts?

A good example of this is clinohumite. Usually, it is an unattractive mineral of the silicate group, and only in a few places can a bright yellow-orange clinohumite can be found. Gemologists from Pamir showed me this stone, and they had quite a collection of samples already. This gemstone strikes with its utter beauty and richness of hues – all the way from deep yellow to orange. You will never see anything like this in any other stone; in fact, clinohumite might have become one of the world’s top stones. But it is just unlucky. My Tajik colleagues say it sells poorly even though their price is more than fair.

PezzottaitePezzottaite TitaniteTitanite TaaffeiteTaaffeite

The problem is that unlike other stones, clinohumite has never had any promotion at all, for several reasons. First is that its unattractive name doesn’t help its cause, but then again, it was invented by some geologists who never thought of selling the stone, let alone it having any market competition, so the first association that came to mind with this stone is “clay” and “humus.” It would make a good name for ore containing lots of useful metals, but it’s definitely not the first name one would choose for a jewelry stone, especially with other beautiful names like paraiba and padparadscha. Secondly, this gem is almost unknown to general public, so to promote it would require a huge amount of money. In fact, this is what I was told when I brought the samples to Thailand. The dealers were entranced by the clinohumite, but nobody was willing to buy it. A third reason for the obscurity of clinohumite is that the deposits are located in Tajikistan, a country that is very unstable and therefore a risky place to set up a business venture.  

There are stones so rare that they occur in only one single place. For example, benitoite; this mineral, like clinohumite, is a silicate. But its fate was a bit different. In the U.S., benitoite is valued and respected first of all because it is mined in that territory. The stone received its name after the location where it was found, the San Benito County in California. It was discovered in 1906, but since then, only very small quantities of this gem have been mined. Also, most of the stones were either non-transparent or too small, weighing up to just one carat. The largest cut benitoite is just 7.8 carats, which, though on display in a museum, is very small in comparison to other gems. However, this stone is incredibly beautiful. It reminds one a bit of sapphire, but has better color play. So the benitoites seen in advertismenets cost much more than sapphire, about $2,000-3,000 per carat.

Recently, another new mineral and wonderful jewelry stone has been discovered: pezzottaite. These are minerals that were discovered while studying the already existing cuts. Good mineralogists and gemologists know about such stones, which are included in most of reference books, but very few people actually know them by sight and can distinguish them. For example, taaffeite was discovered only in 1945 during the study of what was believed to be a pink spinel. Until now, it exists only in several samples. Another rare mineral, singalite, was found in 1952 in Sri Lanka. It had been found earlier, too, but mistaken for another mineral, peridot. Singalite occurs in light-yellow, green, and pink hues.

ClinohumiteClinohumite A hauyne forget-me-not A hauyne forget-me-not PainitePainite

Jewelry varieties of the well known minerals also occur. For example, titanite (sphene). Newbies in the jewelry industry could easily take its green, chrome-containing variety for an emerald. Titanite is found in Mexico and, more recently, in Brazil. Large, bright green sphenes usually come from these two countries, and it also comes from the Urals in Russia. The chrome-containing variety of diopside is known on the market as “Yakut emerald.” This stone, however,  has two major problems: small size and little hardness (only 5,5).

Sphalerite and scheelite also look beautiful when cut, though they are usually mined as ore for, respectively, zinc and tungsten. Any student of geology knows that when such minerals as axinite, danburite, andaluzite, natrolite, and kyanite are cut, the results are able to surprise even the experts. To find a good sample of cassiterite to cut is quite difficult; t gets lost in the tons of cassiterite concentrate, the tin ore.  Wonderful, sparkling gems can be made from the most banal calcite or other carbonates such as bright-red rhodochrosite (manganous carbonate) or transparent or yellowish cerussite (lead carbonate). Their high deflection rate creates a unique color play when the stone is given the appropriate cut.

Even fluorapatite, the mineral that makes up our bones and teet, can be used in jewelry. This stone is surprisingly diverse when it comes to colors. It may be colorless and yellow, green and pink, even deep purple. The crystals from Akzhayliau (Kazakhstan) also feature a strong alexandrite effect.

Some of the stones mentioned above are hard and tough enough to be worn, but still, they are most interesting for those who collect minerals. Though the minerals themselves are quite widespread, their jewelry varieties are often quite rare. One of the most remarkable stones in this respect is sulphur, which sometimes forms large, bright-yellow transparent crystals. Sulphur has a high (over 2) refraction index, so a cut looks wonderful. But such samples are very few. Sulphur’s delicacy, low melting temperature, and sensitivity to slightest temperature changes make it incredibly difficult to cut. One may be afraid to even touch such a stone, let alone cut it. Only very few collections in the world are able to boast a cut sulphur crystal. One of them is the center of attention in the gemology hall of the Ontario Royal Museum in Toronto.

HauyneHauyne SphaleriteSphalerite BenitoiteBenitoite

The only rival of sulphur in respect of to the beauty and complexity of treatment could probably be realgar (arsenic monosulphide). But its samples can be kept only in the dark place, in closed containers. They can stand only a few minutes of light, so it is quite understandable that this is no jewelry stone. However, it is said the Chinese once made jewelry featuring this wonder.

Finally, there are highlights of the jewelry world that would puzzle both gemologist and mineralogist. They will try for quite some time to figure out the stone to no avail. This is not because the mineral is rare and therefore difficult to determine; it is just impossible to imagine that this here mineral is able to produce such color, play, transparency, and size.

There is a mineral called hauynite (hauyne). It was discovered in 1807 and named after one of the founders of crystallography, the French abbot Ren? Just Ha?y (commonly referred to as Abb? Ha?y). This mineral's composition is similar to that of lazurite, and it is formed in the young rocks after the volcanic eruptions (for example, at Vesuvius). Earlier, it could be studied only under the microscope, but later, a few small non-transparent crystals were found. Still later, someone succeeded in cutting this stone, achieving incredible, inimitable bluish-violet ultramarine inserts, a color that is unlike any other hue.

Hauyne is found only by chance and a lot of luck. Any kind of special mining is absolutely out of the question. Price for larger stones (up to 3 carats at least) exceed $10,000 per carat. One of the businessmen I know told me once about a great deal he made: he bought a batch of hauyne for $20,000 and subsequently sold it in Japan for $60,000. It is a pleasure to deal with such rare stones. It is believed that there are up to 200 cut hauyne stones sized over 2 mm in the world, so to feel the pleasure of being unique, one will pay anything.

Fluor apatiteFluor apatite ManganotantaliteManganotantalite

Manganotantalite is a commonly occurring mineral that is sometimes known as tantalite. It is hardly imaginable this stone will ever catch any gemologist’s eye, but its manganese variety is able to shine a light so red, it will easily put even a ruby to shame.

Stilvellite (cerium borosilicate) is still waiting for its time to come. Relatively large crystals of this mineral were found only on the Darai-Piez glacier in Tajikistan, and only a few cut stones are known. Depending on the light, stilvellite changes its color from red-brown to grass green. The same glacier is the home of a totally unimaginable green leucosphenite; all other varieties of this mineral are unsuitable for jewelry.

Hardly anybody knows about painite, an extremely rare oxide once found in Myanmar in the form of bright orange-brown transparent crystals. Another gemstone promoted as ekanite features wonderful green color. While studying inserts made of this gem, the expert would most probably find out that some of them are made of steacyite or recently discovered turkestanit. The problem is that neither of these stones can be worn, because they are all thorium silicates and have a rather strong radiation level. Carletonite, an awesome sky blue stone found in Canada, deserves to be mentioned, as well, and some cuts have been successfully made out of it.

The list of unique jewelry stones is a lot longer, of course, though still not as long as one would think. At the same time, almost any of the 4,000 now-known minerals is able to surprise with unpredictable color or shape.

Finally, it is to be said we did not include descriptions of such well-known stones as garnets, amber, aquamarine, amethyst, peridot, etc., and we excluded them deliberately. That was not our task in this book, but there are many other gemological reference books that include information on these and other stones.