CaB₃O₃(OH)₅.H₂O

This sample of inyoite is displayed in the Smithsonian Museum of Natural History. Inyoite is a oxide mineral of boron with calcium (a borate). Its composition is CaB₃O₃(OH)₅.H₂O. The sample at left is about 10 x 30 cm and is from Sorpresa, Pastos Grandes, Salta, Argentina.