Inyoite, named after Inyo County, California, where it was discovered in 1914, is a colourless monoclinic mineral. It turns white on dehydration. Its chemical formula is Ca(HBO)(OH)÷4HO or CaB<sub>3</sub>O<sub>3</sub>(OH)<sub>5</sub>÷4H<sub>2</sub>O. Associated minerals include priceite, meyerhofferite, colemanite, hydroboracite, ulexite and gypsum.