Sky blue crystals and crystal aggregates of the extremely rare antipinite (IMA 2014-027) from the only known locality worldwide (Pabellon de Pica, Chanabaya, Iquique Province, Tarapacá Region, Chile). Associated mineral is pale green salammoniac. Antipinite is a Copper-Sodium-Potassium Oxalate, which is a very rare combination in Nature since it is a mixture between an organic mineral and an inorganic mineral. — Photo: David Hospital · CC BY-SA 4.0
Antipinite
A rare alkali-copper oxalate mineral found in Chile's Tarapacá Region.
Intro adapted from Wikipedia (CC BY-SA).
Antipinite is an IMA-recognized mineral species in the organic mineral class, with the chemical formula KNa₃Cu₂(C₂O₄)₄.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Not in a structural group, Oxalate structural group.
Key properties: Mohs hardness 2; specific gravity 2.53; Pale blue, almost white streak; Vitreous luster; optically biaxial.
IMA symbol Atp, IMA status: approved, named in 2014.
Found in a guano deposit, as a secondary mineral with guano as the source of oxalate groups and oxidized chalcopyrite, from underlying gabbro, as the source of Cu.
It is found associated with Halite, salammoniac, chanabayaite, joanneumite.
The mineral was named to honor Mikhail Yuvenal’evich Antipin (1951-2013), a Russian specialist in the crystallography and crystal chemistry of organometallic and coordination compounds.