Name two source of sulphur in the earth crust ?

1. Sulphide minerals: Sulphur is commonly found in the earth's crust in the form of sulphide minerals such as pyrite (iron sulphide), galena (lead sulphide), and sphalerite (zinc sulphide).

2. Sulphate minerals: Sulphur is also present in the earth's crust in the form of sulphate minerals such as gypsum (calcium sulphate) and barite (barium sulphate).

1. Pyrite (FeS2)
2. Gypsum (CaSO4·2H2O)