BENITOITE, a mineral discovered in 19o7 near the head waters of the San Benito river, San Benito county, Calif., in veins with natrolite in glaucophane schist. It is a titano-silicate of bar ium crystallizing in the trigonal system, with a hard ness of 6.5 and specific gravity 3.65. It may be colourless or blue, the colour varying sometimes in different parts, and passing to a deep sapphire blue. The blue variety is cut as a gem-stone, and often resembles blue spinel, though its softness distinguishes it from spinel and sapphire.