A telluride mineral is a mineral that has the telluride anion as a main component. Tellurium belongs to group 16 with sulfur and selenium and has similar chemical behaviour, so tellurides are grouped with sulfides in both the Dana and Strunz classification systems.
Tellurides commonly combine with gold, silver, lead, bismuth and platinum-group elements to form economically important minerals. Many tellurides are gold and silver ore minerals, especially in low-temperature hydrothermal gold deposits where gold may be concentrated as tellurides rather than as native gold.
Examples include:
Tellurides are commonly metallic, opaque, relatively dense and soft, with colours ranging from silver-white and lead-grey to brass-yellow. Crystal structures are often cubic, hexagonal or orthorhombic, and many minerals form fine-grained disseminations or intergrowths with native gold, pyrite, chalcopyrite and galena.
Telluride formation is associated with magmatic, volcanic and low-temperature hydrothermal fluids. Under oxidising conditions tellurides are unstable and readily decompose to tellurates or native tellurium, so they are poorly preserved at the surface. Stable telluride assemblages and alteration features can indicate the temperature, sulfur fugacity and tellurium fugacity of ore fluids.
Tellurides are important ore minerals of gold, silver and platinum-group elements, especially in telluride-type gold deposits that lack native gold. Calaverite, krennerite, petzite and sylvanite are important gold ores, hessite and petzite are silver sources, and merenskyite and temagamite may carry platinum-group elements.
Tellurium itself is an important industrial element used in cadmium telluride solar cells, thermoelectric materials, alloys and metallurgical additives. Tellurium is recovered mainly as a by-product of copper electrolytic refining, with a smaller contribution from telluride ores. Demand and recycling value are increasing with the growth of photovoltaics and thermoelectric technology.
Tellurides resemble sulfides in crystal structure and chemical behaviour, but the larger and more polarisable telluride ion favours different structure types and metal associations. Tellurides commonly occur with sulfides, sulfosalts and native elements, forming complex mineral assemblages in ore deposits.
In classification, tellurides belong with sulfides, selenides, arsenides and antimonides in the broader sulfide-and-related group. The Dana and Strunz systems differ slightly in their groupings but both emphasise anion type and metal coordination.