axinite

axinite, borosilicate mineral that occurs most commonly in contact metamorphic rocks and also in mafic igneous rocks. Particularly beautiful crystals occur at Le Bourg d’Oisans, Isère, France, and in San Diego County, Calif., U.S. Transparent axinite of the usual clove-brown colour is sometimes cut as a gem. For chemical formula and detailed physical properties, see silicate mineral (table).