Sulphur (or sulfur)

Native sulphur is the major ore of sulphur. Its primary commercial use is in the manufacture of sulphuric acid (H 2SO 4), which in turn is used in the manufacture of fertilisers and batteries, and forms the basis of many industrial processes. Other uses include fungicides, insecticides, and as a component in gun powder. Pure sulphur is odourless, and the distinctive rotten egg smell associated with it is formed when it mixes with water producing hydrogen sulphide (H 2S) gas. The poor heat conductivity of sulphur makes it brittle when heated and it can crack if held tightly in the hand. The colour of Jupiter's moon Io is due to sulphur volcanism.

Sulphur is widely distributed as native deposits near volcanoes and hot springs, is a component of sulphide minerals, e.g. galena, pyrite, sphalerite etc, and is also found in meteorites. Significant deposits exist in salt domes along the Gulf Coast of the USA, and in large evaporite deposits in eastern Europe and western Asia, and are most likely the result of bacterial breakdown of sulphate minerals.

Chemical composition - S
Hardness - 2
Specific gravity - 2
Transparency - Transparent to translucent
Colour - Yellow
Streak - Yellow
Lustre - Vitreous to earthy
Cleavage/fracture - Poor in two directions / conchoidal, uneven
Crystal habit/mode of occurrence - Prismatic ( bipyramidal, sphenoid [wedge-shaped]), tabular / massive, powdery