Benitoite is a rare blue barium titanium silicate mineral, found in hydrothermally altered serpentinite. It fluoresces under short wave ultraviolet light, appearing bright blue to bluish white in color. First described in 1907 by George D. Louderback, who named it benitoite for its occurrence in San Benito County, California. It is California's official state gem. Benitiote has a rare 5 pointed crystal form, and an even rarer 6 pointed form, "star of David", with about 24 samples known.