Antimonite or Stibnite

Antimonite forms typical prismatic, elongated crystals, often longitudinally striated. It is soft and heavy; in thin flakes it melts in the flame of a match and is soluble in hydrochloric acid.

It is a mineral of hydrothermal origin and is often found associated with other minerals containing antimony.

Antimonite is rather important industrially because antimony is extracted from it and then used in various sectors, metal alloys and medicine, to name only the most important.