Galkhaite is a rare and chemically complex sulfosalt mineral from a group of natural thioarsenites. It is an isometric-hextetrahedral mineral containing antimony, arsenic, cesium, copper, mercury, sulfur, thallium, and zinc. Its formula is (Cs, Tl)(Hg, Cu, Zn)6(As, Sb)4S12, making the mineral the only known natural Cs-Hg and Cs-As phase.
It occurs in Carlin-type hydrothermal deposits. It was named for the Gal-Khaya arsenic-mercury-tin deposit in the Eastern-Siberian region of Russia where the mineral’s type locality is located.
- Category: Sulfosalt minerals
- Formula: (Cs,Tl)(Hg,Cu,Zn)6(As,Sb)4S12
- Crystal system: Cubic
- Crystal class: Hextetrahedral (43m)
- Luster: Adamantine, Vitreous
- Transparency: Opaque
- Colour: Dark orange-red
- Streak: Orange-yellow
- Hardness: 3 on the Mohs scale
- Tenacity: Brittle
- Fracture: Irregular/Uneven, Conchoidal
- Density: 5.4 g/cm3 (Measured) and 5.44 g/cm3 (Calculated)
Occurrence: In hydrothermal Hg–Au deposits. Galkhaite occurs in hydrothermal mercury-gold deposits. It is a rare mineral that is additionally found in the United States, Canada, and newer localities in Iran, Italy, and Kyrgyzstan.
Association: Pyrite, stibnite, cinnabar, metacinnabar, aktashite, enargite, wakabayashilite, orpiment, realgar, getchellite, calcite, fluorite, quartz (Russia); pyrite, realgar, stibnite, orpiment, getchellite, fluorite, quartz (Getchell mine, Nevada, USA).