Alforsite is a hexagonal colorless crystal in the chemical class phosphates and the group apatite. It is found in certain parts of central California, primarily Fresno, Mariposa, and Tulare Counties. It has also been found in Baja California, Mexico.
Sources: http://webmineral.com/data/Alforsite.shtml, http://www.mindat.org/min-112.html, http://euromin.w3sites.net/mineraux/ALFORSITE.html