Formula: CaB3O3(OH)5.4H2O
Hydrated borate containing hydroxyl, inderite group
Specific gravity: 1.875
Hardness: 2
Streak: White
Colour: Colourless, turning white upon partial dehydration, colourless in transmitted light
Solubility: Soluble in hot water and dilute acids

Evaporite deposits

Inyoite occurs along fractures and as nodules in sedimentary borate deposits, associated with meyerhofferite, colemanite, priceite, hydroboracite, ulexite and gypsum (HOM).


At the Qaragol boron mine, Zanjan province, Iran, inyoite is associated with meyerhofferite. Microcrystals of colemanite have been observed between and within the inyoite crystals, and inclusions of inderborite in the inyoite crystals have been detected by XRD. Large inyoite crystals to 9.5 cm have been found at this locality (R&M 92.6.542-544).

At the type locality, the Monte Blanco Mine, Black Mountains, Amargosa Range, Inyo county, California, USA, inyoite is associated with priceite, meyerhofferite and colemanite (Mindat). Meyerhofferite pseudomorphs after inyoite are usual here (AM 25.549).

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