![]() ![]() In addition to quartz, coatings are known on diamond, sapphire, topaz, emerald, opal, apatite, spinel, tanzanite and topaz.Ī new trend is comming up by coating gemstones and artificial products with thin diamond-like layers (DLC - Diamond Like Carbon) or with synthetic diamond (CVD - Chemical Vapor Deposition) and thus change their optical and physical properties. For reasons of cost, both methods are used exclusively for cut (faceted) stones.Īdvances in coating technology in recent years have led to a significantly improved appearance and a steadily growing number of gemstones suitable for this treatment. This makes the surface more resistant to mechanical stress. The second method consists of protecting coated stones with a thin layer of synthetic diamond. This way the delicate surface is protected by the setting, while the color shines from the bottom through the intire stone. Sieber, The first solution to avoid this defect is to apply the coating only to the bottom of a cut stone. The color-bearing layer wears off relatively quickly through everyday use in jewellery.įoto: K. The metal layer has a thickness of only a few atomic layers and is not very resistant to scratches and exfoliation. In the case of topaz, titanium (Ti) produces red colour varieties (trade name "Mystic Fire Topaz") and a mixture of iron and titanium (Fe + Ti) produces golden yellow colours ("Imperial Gold Topaz"). In the meantime, the complete color spectrum of the rainbow is covered. Rock crystals coated with lead show green colors, chromium produces red tones and titanium dioxide a shimmer in rainbow colors (trade name "Rainbow Quartz"). "Mystic Fire Topaz") beside many already known varieties like Citrine, Amethyst, Gold Topaz etc.Ī thin layer of gold (Au) produces light blue tones on rock crystals (trade name "Aqua Aura"), a mixture of gold with platinum produces purple and silvery iridescent shades (trade name "Angel Aura"), indium provides dark blue, tanzanite-like colours ("Tanzan Aura Quartz") and bismuth gives a yellow, citrine-like appearance. As a result, some previously unknown color varieties came on the market (e.g. However, as early as the 1970s it was discovered that the method was appropriate to create artificial color varieties of quartz and topaz for the jewellery market. Originally, the process was developed to give any material new electrical and optical properties. In the plasma, the metal is broken down into its atomic components and then deposited on all objects that are in the vicinity as an anode. ![]() In this process, a metal vaporizes from an electrode that acts as a cathode. The process by which the crystals are coated is called "plasma sputtering" and works like a firing chamber in which a 2000☌ hot plasma is generated. Sieber, They have creativ sounding fantasy names such as "Angel Aura", "Aqua Aura" or "Tanzan Aura Quartz": gemstones with metallic coatings are spreading more and more in the form of cut jewelry and as treated raw crystals. Vapor-coated quartz and topaze are becoming increasingly widespread in the jewelry sectorįoto: K. ![]()
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