sylvanite
nounA pale brass-yellow to silver-white ore of gold and silver, chiefly (Au,Ag)Te2.
nounA native telluride of gold, silver, and sometimes lead.
nounA 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
a silver-white mineral consisting of silver gold telluride; a source of gold in Australia and America