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Written by rdjadmin On May 2, 2013.

When in 1981 the gem trade got wind that ametrine, a combination of amethyst and citrine, could be created from amethyst in the lab by heating and irradiation, the warm welcome it had given this two-tone gem a year earlier became a cold shoulder.

The swift reversal of fortune for this two-tone purple and yellow quartz, and the drop in its price to levels almost equal to regular amethyst now seems unfair. Especially when the trade discovered that most, if not all, ametrine on the market is all natural, from an unusual mine in Bolivia.

Now this two-in-one quartz is staging a comeback, in part because it is championed by some famous gem sculptors, including Germany’s Bernd Munsteiner.

Unlike bi-colored tourmaline, which often combines popular green with equally popular red, ametrine combines popular purple with less popular brown and yellow. To make things worse, at the time ametrine was introduced, citrine had little of the popularity it enjoyed in the 1930s and 1940s or has since begun to enjoy again.

On top of this, demand for citrine was then narrowly focused on its deep brownish- and reddish-orange cognac colors. The gem’s lighter-toned yellows and golds were not nearly as appreciated as they are today. Since these latter hues were mostly what one saw in ametrine, the stone struck many jewelers as bland. So even without the taint of treatment, ametrine might well have bombed.

But its lack of prestige means that ametrine is the most affordable bicolor gemstone. It also means that the gem is an affordable medium for gem scuptors to work in, using the different color areas to add another dimension to their work.

Perhaps what ametrine needs to arouse interest from collectors is cutting as novel as its appearance. In some cases, carvings can show not only yellow and purple but also a warm peach where the two colors blend.

Ametrine can also show striking effects in stand-alone gem carvings. Munsteiner’s work in ametrine shows just how beautiful this affordable bicolored quartz can be: they are more art than adornment.

For jewelry use, ametrine is usually cut in an emerald cut to most clearly display the two-tone effect. When judging bicolor ametrine, look for the attractiveness of the two colors and their proportion. A half-and-half mix with a straight line between the two colors is considered best.


Written by rdjadmin On May 2, 2013.

Money doesn’t grow on trees, but gems do. Or did.

Some 25 to 40 million years ago, in what is now the Baltic region of Europe (Poland, Latvia and Lithuania especially), towering tropical pine forests began to sweat sap profusely. Globs of this sticky, aromatic resin poured down the sides of trees, often trapping leaves, twigs, bark and, occasionally, insects in their paths, and meanwhile snowballing in size. (The same process repeated itself during a later geological epoch in what is now the Dominican Republic and, still later, in what is now Tanzania.)

Imagine, for a moment, these forests with their bejeweled floors and tree trunks. What a spectacular sight they must have been. Eventually, continental drift and an ice age or two took these vast pine tracts underground where their resin globs hardened into a soft, warm, lustrous substance that looks and feels a lot like plastic.

More recently, within the last million years, Stone Age man discovered pieces of this fossilized sap washed up on the Baltic shores. Inviting to the eye and sensuous to the touch, it was only a matter of time before mythopoeic early man imbued these sea jewels with supernatural properties (it was said they came from the sun) and used them for both wear and worship. This fascination continued into and past the dawn of civilization as the golden stone took on great value and significance to, among others, the Assyrians, Egyptians, Etruscans, Phoenicians and Greeks.

Love of amber is as old as mankind. Archaeologists have positively dated amber artifacts as far back as 5000 B.C. No other gem except, perhaps, the pearl, can rival amber for sustained ornamental usage and popularity. The gem has never really gone out of vogue. Between 1895 and 1900, one million kilograms of Baltic amber were produced for jewelry. And well into the 1920s, amber was second only to diamonds in terms of U.S. gem imports.

There are plenty of reasons why amber has enjoyed 70 centuries of adoration.

Frozen Time

To look at a piece of fine amber is to look at a miniature time capsule made and placed in the earth by nature herself. Incredibly, according to Patty C. Rice, author of “Amber: The Golden Gem of the Ages,” more than 1,000 species of extinct insects and crustacea have been found in amber. Studying leaves, twigs and botanical debris found encased in this gem has helped to identify many forerunners of our modern conifers, not to mention plants and flowers. Most importantly, it has helped paleontologists reconstruct life on earth in its primal phases.

But besides preserving the pre-human past, amber resonates with human history. No other gem is so intricately intertwined with the development of civilization and the procession of past societies. Baltic amber was a mainstay of trade and commerce in early Europe and the adjoining Mediterranean region at least as far back as 3200 B.C., by which time Egyptian dynasty and Stonehenge priests were already burying it in tombs, presumably to enable its owners to have good fortune in the afterlife.

Given such veneration, it comes as no surprise that the quest for amber motivated conquest for thousands of years. For instance, the Phoenicians, perhaps the best-known and most enterprising of ancient mariner peoples, opened new sea routes to northern Europe in an attempt to obtain amber direct from, or at least, closer to its source. (By then amber was known as “gold of the north.”) The Romans went one step further and sent armies to annex amber trading and producing areas. Indeed, wrote the great natural historian Pliny during the time of Nero (amber’s most ardent addict), “The price of a figurine in amber, however small, exceeded that of a living, healthy slave.”

The passion for amber wasn’t merely pagan. Clear, colorless amber was considered the most desirable material for rosary beads throughout the Middle Ages. In fact, the Amber rosary bead business was so big that certain orders of knights gained virtual monopolistic control of the gem.

By 1400 A.D. the possession and sale of raw, unfashioned amber was illegal in much of Europe.

“Brand X” Saps

The Baltic region is to amber what Burma is to ruby: its most prized source. Ironically, amber connoisseurs talk almost as admiringly of a reddish-brown Burma amber, the hardest (3 on the Mohs scale) and thus the oldest of all amber yet discovered (the longer amber is buried, the harder it gets). Obviously, hardness, usually 1.5 to 2.5 on the Mohs scale, is not one of amber’s strong points. But it more than compensates for its softness with a range of colors, numbering around 250, including very rare blue and green specimens from Sicily.

Aficionados divide amber into two main groups: clear and cloudy. The clear variety takes a high polish and is very much in demand, particularly in bead form in America. The cloudy type, most often likened to whipped honey in appearance, is preferred in Europe and North Africa and the Middle East.

Believe it or not, Baltic origin is a selling point for amber. Stones from this region contain succinic acid and are known as succinites while those without are known as retinites. To the unaided eye, it is impossible to tell succinite from retinite amber.

It is equally difficult to tell amber from its natural, much more recently created substitutes, the most common of which is copal, formed in African forests within the last 1,000 years. Copal not only resembles amber in appearance, it also contains leaves and insects. To differentiate copal, put a drop or two of ether on the stone in question. If it’s copal, it will turn sticky.

Nevertheless, don’t let ether decide whether the stone is amber. If the stone stays hard, it could just as well be a fake as amber. Plastic look-alike amber has long been a problem, especially since the late nineteenth century and the advent of synthesized plastic imitations such as celluloid, bakelite, and, more recently, bernit, polystrene and polybern. Thankfully, hot-point testing can help in detection of these fakes. Trickier to detect is pressed, or reconstructed, amber that consists of fused natural amber pieces- often with insects inserted. Even all-natural amber is commonly oiled to remove cloudiness, as well as to darken and harden it. It is only fitting that the longest-coveted gem should be paid the supreme flattery of rampant imitation.


Written by rdjadmin On May 2, 2013.

Imagine yourself alive some 2000 years ago and walking down a Roman road. Suddenly you must make way for an ox-drawn cart. Look carefully at the animal and the driver as they pass because there is very likely an amulet on the right horn or the ox and another one on the driver” s upper right arm. If you inquire about these gems, you’ll be told they are moss agates, a type of quartz known for its distinctive dendrite inclusions that often resemble trees and vegetation. According to local lore, this particular form of talismanic gem influences the heavens to grant abundant harvests. That makes moss agate a farmer’s best friend.

Now suppose you walk a little farther and meet a couple of Roman soldiers. Chances are equally good that theyll be wearing quartz amulets, too . This time red or brown in color to give protection against poisonous spiders and snakes as well as to instill courage in battle. Whats more, both farmer and solider alike may be wearing green quartz because it is often recommended by doctors to strengthen eye sight.

Both the patterned and the single-color gems are classified as chalcedony, a cryptocrystalline quartz composed of tiny fibers and grains. Those with patterns caused by deposits of silica and mineral oxides which accumulate over time are generally known as a subspecies called agate. Agates with simple bandings of color are called banded agates. Those with patterns reminiscent of nature scenes and landscapes are called scenic agate. Fire agate boasts iridescent layerings that seem to glow and smolder like embers. Lace agate derives its name from its banded swoops and swirls. Those with inclusions that remind of vegetation are moss agate.

In recent years, the most popular single-colored chalcedony has been a highly translucent slate-blue variety from Namibia. Among patterned chalcedonies, moss, fire, and banded agate remain popular, as much for their unique individual pattern, no two alike, as for their powers.

African Aquamarine

Written by rdjadmin On May 2, 2013.

“There are blues that make you happy and there are blues that make you sad,” an old song goes. Until recently, lovers of aquamarine have known mostly the latter. Now there is flood of the former. It’s about time.

Anyone sick and tired of seeing the anemic and powdery blues of Chinese and Brazilian aquamarine for the past few years will be crying tears of joy when they feast their eyes on the aqua coming from Africa in the past two years. These are stones with the deep soothing menthol blues for which this beryl is justly famous.

But don’t expect to see aquas with this kind of tangy, bracing color on shop-at-home television or in discount stores. Superior-quality aqua costs closer to $1,000 per carat in sizes between 3 and 10 carats. That makes it connoisseur material, at least 50 percent of which goes to Japan. There consumers want aqua that lives up to the name-and are willing to pay handsomely for the privilege of owning handsome stones.

Who can blame them? For years, there wasn’t much deep-color aquamarine on the market. Then, in the late 1980s, Zambia started to mine goods which rated 9 1/2 on a scale from one to ten. After another dry spell of dark colors in the mid-90s, Mozambique, joined later by Nigeria, began producing roughs with aftershave and mouth-rinse blues in enviable earnest-enough to establish Africa as the all-time leader in quantity and quality for fine aqua. In our talks with dealers, only stones from the Santa Maria deposit in Brazil, which was active in the 1940s and 50s, received higher praise. Yet although it has been more than half a century since Brazil produced aqua that excelled Africa’s best, Africa is only now receiving its due. Ironically, the recognition comes just when supplies from Africa are down sharply and suddenly. What gives?

Pretty in Platinum

Aqua, like many pastel-color gems, has benefited from the popularity of platinum and white gold. Demand is strongest in sizes between 2 and 5 carats between $500 and $1,000 per carat.

Adding to demand is the fact that African goods look very good in even smaller sizes down to 50 points. And here aqua may be one of the best buys in colored stones these days. It is far easier to find better-looking aqua in small sizes than in tanzanite.

But such bargain prices won’t hold if the worrisome decline in supplies of rough since late last year continues much longer. Granted, catastrophic flooding in Mozambique could have disrupted mining for a while.

At present, the two main sources of fine African aquamarine are Mozambique and Nigeria. But Zambia and even Malawi may also be contributing to the pot. Between all of these active producers there should sooner or later be a surge in supplies of rough. The question remains: Will it offset surges in demand?

African aquamarine cut by John Dyer of Precious Gemstones Co.

African Amethyst

Written by rdjadmin On May 2, 2013.

Although Africa has been producing amethyst for more than a decade, the news was pretty much of a trade secret until only a few years ago. Now, with this deep purple gem very much in vogue (it is also the February birthstone) jewelry manufacturers and retailers are specifying the African variety when ordering amethyst.

Not that they always get it.

To the contrary, stones labeled “African” stand more than a 50/50 chance of originating in Brazil (a beehive of amethyst mining) or Uruguay (a major new source). And despite an easy-to-perform test to distinguish natural from synthetic amethyst recently made public by the Gemological Institute of America, Santa Monica, California, parcels can still be salted with splendid replicas of nature manufactured in Russian and Japanese labs.

In short, Africa has become more a synonym than a source for amethyst of the best color and appearance being found. To be sure, the ideal for this quartz remains the Siberian variety. But since Siberia is considered a defunct source, stones from Africa now represent the point closest to the ideal that dealers can hope for.

Even specialists in South American amethyst concede that Africa currently sets the standard of excellence for this gem. “African stones are normally better than South American,” says a Los Angeles cutter. “They’ve usually got a royal purple with reddish overtones that is very beautiful.” This cutter admits he would like to sell African amethyst but says supplies of rough are too hard to come by and much too expensive when they are available.

Yet other amethyst dealers are willing to pay extra to get African material. “Money really isn’t the problem,” says a Seattle importer. “It’s the waiting.”

So it would seem. In July 1985, during a buying trip to Africa, a dealer promised him 100 kilos of Zambian amethyst rough. He received the first fifth of his order, 20 kilos, 18 months later.

What is it about African amethyst that makes dealers put up with so much to get it?

A Preference For Dark

African amethyst, like African aquamarine, tends to come in much smaller sizes than its South American counterparts. But what it lacks in size, it more than makes up for in color.

For some unknown reason, it is Africa’s forte to cram incredible color intensity into small crystals. Until African amethyst and aqua came on stream in full force in the early 1980s, the market had to make do with, at best, medium color intensities for these gems in sizes under 3 carats. In fact, pale lilac shades, known in some quarters as “Rose of France,” were often all that consumers got to see. Few knew the deep purple stones that inspired the Greeks to name the gem amethystos, which means “not intoxicated,” and made them earnestly believe that drinking wine from amethyst cups would prevent drunkenness.

All that changed as demand for calibrated stones, generally under 2 carats, grew, and Africa’s darker-toned amethyst and aqua gave manufacturers small stones that had deep, punchy colors- enough to allow the market to shift its preference in small sizes from medium to dark stones. If anything, African stones were often too dark, plagued by what gemologists at the American Gem Market System, Moraga, California, Have dubbed “extinction,” areas blacked out due to over-saturation of color.

Alas, small- both in terms of sizes and supplies- is just about all there is when it comes to African amethyst. Stones of 10 carats or more are rarities. And finding fine stones of 5 or 6 carats requires patience. Come to think of it, routine requests for decent-quality calibrated sizes may call for a search party.

And no wonder. An American dealer living in Zambia, Africa’s principal producer of amethyst, who is one of two cutters in that country registered to buy rough from Mindico, the state-run gem sales agency, reports having been allocated a meager 5 kilos of amethyst for one entire year! Of this, only 5% was cuttable.

Poor Pickings for U.S.

This American might have received more goods if he were a big spender to begin with. Since he isn”t, far more preferential treatment is being accorded to consortiums from centuries including Taiwan, Japan and Germany willing to buy in tremendous bulk. As a result, smaller-fry rough buyers are squeezed out of the African market and must rely on secondary sources in places such as Hong Kong, Thailand and, recently, South Korea, the last coming on very strong as a cutting center for amethyst and irradiated blue topaz.

The goods made available to them from these sources are very often the rejects the consortiums put on the market after sorting through goods and taking the best for themselves.

Luckily for small dealers, a smattering of Zambian goods can somehow be found, as well as increasing but still minuscule production from Tanzania, Africa’s next great hope for amethyst. Recently, Namibia has pitched in with excellent stones, but production is still limited and future supply a question mark.