Lyukait

Lyukait is a mineral consisting of copper(I) sulfide, CuS. It is a member of the sulfosalt group and is known for its metallic luster and dark gray to black color. Lyukait crystallizes in the hexagonal crystal system, often forming in massive or granular aggregates. It is typically found in hydrothermal veins and as a minor constituent in copper-bearing ore deposits.

The mineral was first described in 1966 and is named after the Lyukay deposit in the Republic of Sakha, Russia, where it was discovered. Lyukait is relatively rare and not a significant ore of copper. Its specific gravity is around 4.5 g/cm³, and its hardness is approximately 3 on the Mohs scale. It is insoluble in common acids.

Geologically, lyukait is often associated with other copper sulfides like chalcocite, bornite, and chalcopyrite, as well as minerals such as quartz and calcite. Its formation is typically linked to low-to-medium temperature hydrothermal processes. While not economically important for copper extraction, lyukait is of interest to mineralogists due to its unique chemical composition and crystal structure. It can also be found in some extraterrestrial meteorites, indicating its formation in diverse geological environments.