Blue stone

Blue stone is a generic mineral description commonly applied to a variety of minerals. Perhaps the most common reference is to the hydrated copper (II) sulfate mineral, chalcanthite. The name "blue stone" is also applicable lazurite, the core comstituent of lapis lazuli, a sulfide of sodium aluminium silicate in the sodalite group. The term bluestone is also used for the dolerite stones at Stonehenge.

Other uses of the name blue stone may refer to blue-grey building stone or paving material. In Australia a bluish variety of basalt is widely used for building.

The name should not be confused with blue john, which is a blue/purple variety of fluorite, also known as fluorspar, found in Derbyshire, England.