Lapis Lazuli

la'pis laz'u-li, a mineral much used as a gem and for decorative purposes. As a rule it is without cleavage. It is harder than glass. It consists of silica, alumina, iron, soda, carbon, and a trace of sulphur. The color is usually a deep blue, though it is occasionally violet, green, red, or even colorless. It occurs in small masses in crystalline limestone or in gneiss. It is found only in a few localities. The Old World supply is drawn chiefly from Asia--China, Tibet, Persia, Tartary, and the vicinity of Lake Baikal. The Andean region of Chile and Peru yields fine specimens. The exquisite blue pigment or artists' dye known as ultramarine blue is formed by pulverizing this mineral into a fine powder.