Stibnite Composition, Crystallization, Structure and Occurrence

Composition. Antimony trisulphide, Sb₂S₃ = Sulfur 28.6, antimony 71.4. Sometimes carries gold or silver.

Crystallization. Orthorhombic. Slender prismatic habit, prism zone vertically striated. Crystals often steeply terminated. Often in radiating groups. Crystals sometimes curved or bent.

Structure. In radiating crystal groups or in bladed forms with prominent cleavage. Massive, coarse to fine columnar.

Physical Properties. Perfect cleavage parallel to brachy-pinacoid. H. = 2. G. = 4.55. Metallic luster, splendent on cleavage surfaces. Color and streak lead-gray.

Test. Very easily fusible at 1. B.B. on charcoal gives dense white coating of antimony trioxide and odor of sulfur dioxide. When roasted in O.T. gives nonvolatile white sublimate on bottom of tube and a white volatile sublimate as ring around tube. Heated in C.T. gives a faint ring of sulfur and below a red (when cold) deposit of oxysulphide antimony. Characterized by its bladed structure, perfect cleavage in one direction, its lead-gray color and soft black streak.

Occurrence. Deposited by alkaline waters in connection usually with quartz. Found in quartz veins or beds in granite and gneiss. Sometimes occurs as a replacement in limestones and shales, probably owing its origin to hot spring deposits. Often associated with intrusive rocks. Associated with other antimony minerals, as the products of its decomposition, and with galena, cinnabar, sphalerite, barite and sometimes gold. Found in various mining districts in Saxony, Rumania, Bohemia, Tuscany, central France, etc. Occurs in magnificent crystals in Province of Iyo, island of Shikoku, Japan. Important deposits occurs in the Province of Hunan, China; also in Borneo, Peru, Mexico. Found in quantity only sparingly in the United States, the chief deposits being in California, and Idaho.

Use. Used in various alloys, as antimonial lead for storage batteries, as type, pewter, Babbitt and Britannia metals and antifriction metal. The sulfide is employed in the manufacture of fireworks, matches, percussion caps, etc. used in vulcanizing rubber. Used in medicine as tartar emetic and other compounds. Antimony trioxide is used as a pigment and for making glass.