Vladimir Bukanov. Russian Gemstones Encyclopedia
SYNTHETIC GARNETS (Synthetisch Granate—Synthétique grenades——интетические гранаты), (rare-earth), named after the similarity of their structure with the same of garnet granatites or garnetoids.
Composition & Properties. General formula is A3B2(BO4)3, where A – yttrium and lanthanides; B – aluminum (Al3+), gadolinium (Ga3+), iron (Fe3+) and others. Oxides. Cubic system. Hardness 8.5. Density 4.5. There are artificial gems with the structure of garnet, which are used as rough material for faceting. Because the synthesis of garnets is very labor-intensive and expensive, they prefer to produce artificial material of alternating composition on the base of the garnet structure with the group name of synthetic garnets. Predominance of admixtures of rare-earth elements in their composition was the reason of their name – rare-earth garnets. They were synthesized for the quantum electronics in 1960-s, but because of their perfect jewelry properties, they became widely used as rough material for faceting. The most widely spread among synthetic rare-earth garnets received from melt is synthetic yttrium-aluminum garnet (YAG) –Y3Al5O12 and close to it synthetic yttrium-aluminum perovscite (YAP), or synthetic yttrium aluminate, also synthetic yttrium orthoaluminate – YAlO3, translucent, colorless, rose, violet and green. In 1969-1978-s YAG as an imitation of diamond was produced in significant volumes – up to 40 million ct. per year. There are also colored varieties of YAG, including green one used for the imitation of demantoid. Without admixtures there synthetic garnets are colorless but they can display various tones because of different admixtures. The wide scale of these admixtures as well as the quantity of firms producing such materials led to a great amount of their trade names. In 1973, they invented synthetic gadolinium-gallium garnet (GdGaG or GGG) especially for the imitation of diamond. Beside mentioned rare-earth garnet, there are other artificial materials: synthetic gallium-aluminum garnet (GaAG, or GAG) – produced since 1978, synthetic yttrium-gallium garnet –Y3Ga5O12 (YGaG or YGG), produced since 1978, synthetic lanthanum-indium-gallium garnet (LaInGaG or LIGG), synthetic neodymium-gallium garnet (NdGaG or NGG), synthetic samarium-gallium garnet (SmGaG or SGG), synthetic yttrium-ferrous garnet (YFeG or YFG) – produced since 1978. Obviously, one of the varieties of synthetic garnets is synthesized in France oolongolite (oulongolite) of rose color, which depends on the admixture of chromium. Synthetic yttrium-aluminum-gallium garnet (YAGaG or YAGG) contains the admixture of vanadium, which gives it all the scale of green tones; and the content of chromium produces reddish dot effects in faceted gems, which are seen in artificial light. That’s why such material can be used for the imitation of tsavorite colored with vanadium. Synthetic yttrium-thorium garnet (YThG or YTG) has been produced since 1970 under the trade name yttralon. Synthetic yttrium iron garnet – Y3Fe5O12 (YIG), black. High speed of its growth and large size of its crystals make them available in price for many jewelers. The specifics of the composition and properties of this material make it possible to differ it from natural gemstones.
Synonyms. Synthetic yttrium-aluminum garnet (YAG) – Carolite | Cirolite | Crycolit | Diamanite | Diamite | Diamogem | Diamogen | Diamolin | Diamonair | Diamonaura | Linde simulated diamond | Diamond-brite | Diamone | Diamongem | Diamonte | Diemlite | Di YAG | Kimberly gem | Geminair | Geminer | Hamatite | Hemino | Rigeleyre | Triamond | Yttrogarnet.
Synthetic gadolinium-gallium garnet (GdGaG) – Galliant | Diamonique.