What is Calaverite?
Calaverite is a gold telluride and an important gold ore mineral, recognised by brass-yellow to silver-white metallic crystals and very high density.
Mineralogy and structure
The reference formula is AuTe2. Calaverite belongs to the sulfides and crystallises in the monoclinic system. Calaverite is monoclinic and closely related to krennerite, but it has no cleavage of the type characteristic of krennerite. Collectors value well-formed metallic crystals and documented association with native gold, quartz and fluorite.
Colour and appearance
Typical colours include brass yellow, silver white and grey. For small or complex mineral species, crystal size, transparency, lustre and matrix association are often more diagnostic than colour alone.
Formation and localities
Calaverite forms in or is associated with epithermal and hydrothermal gold-telluride deposits. Important documented localities include Cripple Creek in Colorado, California, Finland, Romania and other gold districts. A precise mine or geological setting is preferable to a broad country label when it is known.
Collecting and care
Calaverite is best treated as a labelled reference or collector specimen. Protect fragile crystals from impact and humidity changes. Arsenic-, cadmium-, lead-, thorium- and selenium-bearing minerals should not be cut, ground or used in jewellery; wash hands after handling and keep them away from food and children.
