動漫之力5同人誌販售會，《寶石之國》南極石cosplayer站姿右側。 — Photo: Gaku [ 岳 ] · CC0
Antarcticite
A rare hydrated calcium chloride that forms colorless needle crystals and greedily pulls moisture from the air.
Intro adapted from Wikipedia (CC BY-SA).
Antarcticite is an IMA-recognized mineral species in the halide class, with the chemical formula CaCl₂·6H₂O.
It crystallizes in the hexagonal crystal system (space group P321).
Key properties: Mohs hardness 2–3; specific gravity 1.715; Vitreous luster; refractive index 1.513; optically uniaxial.
IMA symbol Atc, IMA status: approved, named in 1965.
A precipitate from highly saline brines under very arid conditions (Don Juan Pond, Antarctica; Bristol Dry Lake, California, USA); in stratified fresh to brackish to salt water columns in onshore “blue holes” (North Andros Island.
It is found associated with Halite, gypsum, celestine (Bristol Dry Lake, California, USA).
The name refers to its occurrence on the continent of Antarctica.