Sylvanite

noun

1. A pale brass-yellow to silver-white ore of gold and silver, chiefly (Au,Ag)Te2.
2. A native telluride of gold, silver, and sometimes lead.
3. A telluride of gold and silver, (Au, Ag)Te2, of a steel gray, silver white, or brass yellow. It often occurs in implanted crystals resembling written characters, and hence is called graphic tellurium. H., 1.5-2. Sp.gr., 7.9-8.3.
4. Silver gold telluride, a soft metallic mineral ranging in colour from steely gray to almost white.
5. a silver-white mineral consisting of silver gold telluride; a source of gold in Australia and America