Copper sulphate, blue stone, blue vitriol are all common names for pentahydrated cupric sulphate, CuSO45H2O, which is the best known and the most widely used of the copper salts. Indeed it is often the starting raw material for the production of many of the other copper salts. 

Today in the world there are more than 100 manufacturers and the world's consumption is around 275,000 tonnes per annum. It is estimated that approximately three-quarters of this is used in agriculture, principally as a fungicide, but also for treating copper-deficient soils.

Uses

Copper sulphate is a very versatile chemical with as extensive a range of uses in industry as it has in agriculture. Its principal employment is in agriculture, and, up to a generation or so ago, about its only uses in industry were as a mordant for dyeing and for electroplating. Today it is being employed in many industrial processes:

• The synthetic fibre industry has found an application for it in the production of their raw material.
• The metal industry uses large quantities of copper sulphate as an electrolyte in copper refining, for copper coating steel wire prior to wire drawing and in various copper plating processes.
• The mining industry employs it as an activator in the concentration by froth flotation of lead, zinc, cobalt and gold ores.
• The printing trade takes it as an electrolyte in the production of electrotype and as an etching agent for process engraving.
• The paint industry uses it in anti-fouling paints and it plays a part in the colouring of glass.