List the important sources of sulphur.

Explanation

Sulphur mainly occurs in the earth's crust in the combined state primarily in form of sulphates and sulphides.
Sulphates : Gypsum, `CaSO_(4).2H_(2)O`, epsom salt, `MgSO_(4).7H_(2)O`, baryte, `BaSO_(4)`, etc.
Sulphides. Galena, PbS, zinic blende, ZnS, copper pyrites, `CuFeS_(2)`, iron pyrites, `FeS_(2)`, etc.
Traces of sulphur occur as `H_(2)S` and in organic materials such as eggs, proteins, garlic, onion, mustard, hair and wool.