White single crystal of the very rare borate aristarainite from the TL in Argentina (Tincalayu Mine, Salar Del Hombre Muerto, Los Andes, Salta, Argentina). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Aristarainite
Aristarainite is an IMA-recognized mineral species in the borate class, with the chemical formula Na₂Mg[B₆O₈(OH)₄]₂·4H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/a).
Key properties: Mohs hardness 3.5; specific gravity 2.027; Vitreous luster; optically biaxial.
IMA symbol Ais, IMA status: approved, named in 1973.
Found in a playa evaporite sequence (Tincalayu deposit, Argentina); at a desert borax spring (Eagle Borax Spring, California, USA).
It is found associated with Borax, kernite, rivadavite, ezcurrite, ameghinite, mcallisterite, kurnakovite, searlesite, probertite, ginorite, tincalconite, ulexite, halite.
The mineral was named to honor Professor Lorenzo Francisco Aristarain (1926–), Argentine mineralogist specializing in borate deposits, La Plata University, Buenos Aires, Argentina.