The mineral was first discovered in Saxony by A. Breithaupt in 1817, and named by him from the Greek amblus, blunt, and gouia, angle, because of the obtuse angle between the cleavages. Later it was found at Montebras, dep.Creuse, France, and at Hebron in Maine; and on account of slight differences in optical character and chemical composition the names montebrasite and hebronite have been applied to the mineral from these localities. It has been discovered in considerable quantity at Pala in San Diego county, California, and at Caceres in Spain. Amblygonite occurs with lepidolite, tourmaline, and other lithia-bearing minerals in pegmatite veins. It contains about 10% of lithia, and, since 1886, has been utilized as a source of lithium salts, the chief commercial sources being the Montebras deposits, and later the Californian.