Review of imitation diamonds

Red Jasper Stone

The high cost and inaccessibility of diamonds – cut diamonds of various degrees of color – gave rise to the desire to create more or less successful imitations of precious jewelry. Centuries ago, natural minerals (and glass) were used as materials for counterfeiting. Moissanite stone has become one of the leaders of the modern stage of the race for brilliant brilliance.

The zirconium dioxide crystal, grown in the early 70s of the last century at the Physics Institute of the USSR Academy of Sciences, began its career as a jewelry insert earlier than moissanite. Visual properties of cubic zirconia they bring it so close to a diamond that at first glance it is not always possible to distinguish between a natural gem and an artificially grown stone.

However, jewelers know how to distinguish a diamond from a cubic zirconia. The thermal conductivity of cubic zirconia is 200-500 times lower than the thermal conductivity of diamond! By measuring the amount of heat energy passing through the stone, most inexpensive electronic gemstone authenticators come to the right verdict.

In general, counterfeit diamonds are numerous and varied. Hand-made jewelry amazes sometimes with wit and accuracy of copying, and sometimes also with the helplessness of attempts. Let’s take a closer look at them.

Moissanite occurs naturally …

… our planet is very rare and in trace amounts. Therefore, it is not surprising that the mineralogists of the past left only records of the finds and did not leave any stone samples. Although, in kimberlite pipes, individual crystals of moissanite can theoretically be found.

Meanwhile, industrial synthesis of carbon-silicon material has been going on for several decades. Carborundum (this is the technical name for the SiC compound) is used as an abrasive. Its outstanding jewelry properties became known only recently. Only at the end of the 90s of the last century, the world saw with surprise: cut moissanite sparkles stronger than a diamond!

True, it has not yet been possible to get rid of the dull “dusty” greening in the stone. And the price of artificial moissanite is too high. So, this stone wins the race for primacy among successful imitations of a diamond with a very small (sometimes temporary) lead of the long-term leader.

Cubic zirconia – a domestic diamond for the people

There are countless natural diamonds in Russian mines. But they are expensive, and the industry consumes a lot of them – but if they had given free rein, all the mining would have gone to diamond abrasives. On the other hand, crystals of zirconium dioxide ZrO2 grown in the FIAN laboratories turned out to be a suitable material for imitating a diamond.

Characterized by an almost imperceptible difference in the play of light compared to a diamond, cubic zirconia is produced in the same color shades that are characteristic of natural diamonds. The advantages of the stone include its high transparency and sufficient hardness.

In all physical parameters, cubic zirconia approaches a diamond, but in terms of price it is incredibly far from a diamond. This prompts scammers to pass off an artificial crystal as a natural gem.

The confusion is added by the reluctance of Western gemologists to call the stone an original and recognizable name. There are several different types of artificial minerals in use. Most of the manufacturers of cubic zirconia on the labels prints the abbreviation “CZ”, which stands for “zirconium cube” in our country. Which also sounds strange, but still better than the mimic Diamonds QI.

Grenades explode with diamond sparks

In nature, garnet is a complex silicon oxide, always colored. In artificial production, garnets are also made colorless, which allows fraudsters to pass them off as diamonds.

Half a century ago, physicists needed materials to build lasers. Crystals of yttrium-aluminum garnets turned out to be suitable for imitation of diamonds. True, the indicators of the visual appeal of YAG are not too close to the parameters of diamond. The refractive index of a carbon crystal is many times higher than that of yttrium-aluminum garnet.

However, YAG is perfectly polished, and the brilliance of its edges is blinding no worse than the brilliance of diamond edges. The first attempt to imitate a large diamond was made in 1969 and was successful. The seventy-carat diamond and its YAG replica looked like two drops of water. Until they were near … The diamond (cut with a pear) scattering beams of colored rays was noticeably different from the coldly shiny artificial garnet of the same shape.

The price of YAG is about 20 times lower than the price of natural diamond, so there is a demand for stone (mainly in English-speaking countries).

Gadolinium-gallium garnet is devoid of disadvantages of YAG. Possessing the same ability to shine as a diamond, YYY approaches a diamond in terms of light refraction. The fake jewelry industry clapped its hands at learning about the wonderful properties of crystal – but prematurely.

GGG, as it turned out, is easily electrified and actively collects dust. Its hardness is insufficient for making jewelry inserts. Excessive fragility entails the risk of edge damage, even with careful wearing of the jewelry. Little of! Under the influence of sunlight, gadolinium-gallium garnet turns dirty brown, brown. At the same time, the prime cost of the crystal is high, and its production is not particularly profitable. So today only one company in the world produces jewelry from YGG (if it has not stopped yet).

Strontium titanate: the play of light is stronger than diamond!

Created in 1953 as a possible substitute for gem-quality crystalline carbon, strontium titanate SrTiO3 delighted both scientists and experts with its appearance. The sparkle of his cut crystals in all respects surpassed the best diamonds, and the artificial decoration did not go into the series, but flew.

Unfortunately, it soon became clear that the low hardness (just above 5 points on the Mohs scale) makes the stone short-lived. In addition, titanium-strontium oxide is fragile: even a soft compression, not a shock, can split a jewelry insert.

A desperate attempt by jewelers looked like attempts to glue a substrate made of fragile, but beautiful strontium titanate with a “hat” of leuco sapphire or artificial spinel. Decades of experiments did not lead to a miracle: all the adhesives used sharply reduced the decorative effect of the product. According to unconfirmed rumors, modern Japanese craftsmen have learned to fuse a strong “head” on a titanate base – however, there are no such products on the market. Apparently, the profitability of this production is rather low … It is also

unprofitable to manufacture jewelry inserts, more or less authentically imitating a diamond, from other titanates – barium and calcium. The cost price of these crystals is such that jewelry with them is just right to sell more expensive than diamond sets.

An important optical feature inherent in all titanates negates their decorative qualities. The glare and flares produced by crystalline titanates are very bluish. This shine looks spectacular, but … the color palette of the diamond play of light is immeasurably richer.

Rutile is a veteran of synthetic diamond imitators

Rutile – titanium dioxide TiO2 – is often found in nature, mostly in the form of needle-like crystals and their intergrowths, reminiscent of outlandish flowers or sea urchins. Post-war chemists contrived to grow rutile crystals suitable for gem-cutting.

The cut rutile showed a play of light unattainable for either natural diamonds or other artificial stones. However, the high parameters of light refraction did not allow the lower edges of the jewelry to “work” – and this depleted the light picture …

In addition, rutile is not colorless (it is not known exactly why). At best, it is straw yellow! And although technologists from different countries from time to time publish triumphant reports on the production of colorless rutile, we are talking either about needle crystals unsuitable for jewelry processing, or about thin films on a quartz base.

By the way, even the best examples of jewelry rutile are grown in the form of thin columnar formations. Therefore, rutile imitations of a diamond are usually small in size. And because of the low strength and low hardness of the stone, they are also rare.

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