Tellurium is a not very abundant element, and can be found associated to the gold, copper or sulfur ores. The element occurs in small amounts in minerals like the altaite (PbTe), the calaverite (AuTe2), the coloradoite (HgTe), the ricardite (Cu4Te3), the petzite (Ag3AuTe2), the silvanite ((Ag,Au)Te2) and the tetradimite (Bi2Te2S). Tellurium can also be found in the native state and in the dioxide form (TeO2). The main tellurium deposits are located in Canada, in the USA (Montana, Utah and Arizona) and in Peru.