TELLURIDES are a class of rare minerals composed of tellurium combined with metals such as gold, silver, or bismuth, and some are precious metals. Often found in deep, gold-bearing geological deposits, they can display dark gray, silver, bronze, and metallic hues. This silky alloy of taupe and onyx black, possesses a primeval, lustrous appearance and a rich and ancient character, as though it too has been shaped by the natural chemistry of ancient Earth.