Antimony in its elemental form is a silvery white, brittle crystalline solid that exhibits poor electrical and heat conductivity properties.   Commercial forms of antimony are generally ingots, broken pieces, granules, and cast cake.  Other forms are powder, shot, and single crystals.  Estimates of the abundance of antimony in the Earth's crust range from 0.2 to 0.5 parts per million.  Antimony is chalcophile, occurring with sulfur and the heavy metals, lead, copper, and silver.  Over a hundred minerals of antimony are found in nature.  Stibnite (Sb2S3) is the predominant ore mineral of antimony.  The most important use of antimony metal is as a hardener in lead for storage batteries.  The metal also finds applications in solders and other alloys.  Antimony trioxide is the most important of the antimony compounds and is primarily used in flame-retardant formulations.  These flame-retardant applications include such markets as children's clothing, toys, aircraft and automobile seat covers.

USGS - http://minerals.usgs.gov/minerals/pubs/commodity/antimony/