The average cost of tellurium is $0.18 per gram. A brittle, mildly toxic, silvery-white metalloid, tellurium (Te) is a chemical related to selenium and sulfur. Although several gold deposits contain tellurium minerals, the main commercial source for tellurium is as a by-product of copper and lead production. Tellurium is primarily used in alloys, mainly in copper and silver. It has no biological function. Commercial-grade tellurium is usually marketed as minus 200-mesh powder but is also available as ingots, sticks or lumps.