Discovered in 1450. Elemental antimony is generally found in one of two allotropes and has both metallic and non-metallic properties. The main source of this element is Stibnite (Sb₂S₃), an ore which whilst being widely distributed is not very plentiful (hence the abundance of only 0.2 ppm of antimony within the earth's crust). Antimony is a relatively stable element and is not attacked by dilute acids or alkalis. It is a poor electrical and thermal conductor. Applications of antimony and its alloys include its use as an alloying element for hardening other metals, a bearing material and in batteries. High purity antimony is used in the semiconductor industry.