List the important sources of sulphur.

Sulphur mainly exists in combined form in the earth’s crust primarily as sulphates [gypsum (CaSO₄.2H₂O), Epsom salt (MgSO₄.7H₂O), baryte (BaSO₄)] and sulphides [(galena (PbS), zinc blends (ZnS), copper pyrites (CuFeS₂)].

Sulphur occurs in the earth’s crust in the combind state primarily in the form of sulphates and sulphides.

(i) As sulphates: Gypsum, (CaSO₄.2H₂O), Epsom salt (MgSO₄ 7H₂O), Baryte (BaSO₄) etc.

(ii) As Sulphides: Galena (PbS), Zine blende (ZnS), Copper pyrites (CuFeS₂), Iron pyrites (FeS₂) etc.

Traces of sulphur occur as H₂S and in organic matter such as eggs, proteins, onion, mustard, hair and wool etc.