Outstanding white and colorless crystals of the rare Na borate mineral ameghinite from the type (Tincalayu Mine, Salar Del Hombre Muerto, Los Andes, Salta, Argentina) and only known locality worldwide in Argentina. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Ameghinite
Ameghinite, Na[H4B3O7] or NaB3O3(OH)4, is a mineral found in Argentina. It is a soft mineral with a Mohs hardness of 2–3. Ameghinite has a monoclinic crystal system. It was first described in 1967 for an occurrence in the Tincalayu Mine, Salar del Hombre Muerto, Salta, Argentina. It was named for Argentine geologist brothers, Carlos Ameghino (1865–1936) and Florentino Ameghino (1854–1911).
Intro adapted from Wikipedia (CC BY-SA).
Ameghinite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula NaB₃O₃(OH)₄.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: Mohs hardness 2.5; specific gravity 2.03; Vitreous luster; optically biaxial.
IMA symbol Agh, IMA status: approved, named in 1966.
Formed in massive borax in a borate-rich playa.
It is found associated with Tincalconite, borax, ezcurrite, rivadavite.
The mineral was named to honor two brothers, Carlos Ameghino (1865–1936) and Florentino Ameghino (1854–1911), Argentine geologists.