White crystal aggrgates of the extremely rare Mg-Al carbonate mineral indigirite from the TL in Russia (Sarylakh Deposit, Indigirka River Basin, Sakha Republic, Russian Federation) and only one of the two known localities worldwide. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Indigirite
Indigirite is an IMA-recognized mineral species in the carbonate class, with the chemical formula Mg₂Al₂(CO₃)₄(OH)₂·15H₂O.
It is a member of the Artinite structural group.
Key properties: Mohs hardness 2; specific gravity 1.6; Vitreous to silky luster; optically biaxial.
IMA symbol Idg, IMA status: approved, named in 1971.
A rare filling in cracks in shale in the oxidized portions of a hydrothermal vein Au–Sb deposit.
It is found associated with Gypsum, gibbsite, kaolinite, hexahydrite, melanterite, amorphous Fe oxide, stibnite, quartz.
The name refers to the Indigirka River, Russia, near where the first specimens were collected.