Galkhaite: Properties and Occurrences

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.

General Information

  • Category: Sulfosalt minerals
  • Formula: (Cs,Tl)(Hg,Cu,Zn)6(As,Sb)4S12
  • Crystal system: Cubic
  • Crystal class: Hextetrahedral (43m)

Fig: Galkhaite

Properties

  • 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).

 

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