Explanation:
Sulphur is a non-metallic chemical element with the symbol ‘S’ and atomic number 16. It is found in earth’s crust in various forms such as elemental sulphur, sulphide ores, and sulphate ores. Let’s discuss these forms in detail:

Elemental Sulphur:
Elemental sulphur is the most common form of sulphur found in nature. It is also known as native sulphur and is found in volcanic regions, salt domes, and sedimentary rocks. It is a bright yellow, non-metallic, and odourless substance that is insoluble in water but soluble in carbon disulphide. It is used in the production of sulphuric acid, fertilizers, and gunpowder.

Sulphide Ores:
Sulphide ores are compounds of sulphur with metals such as copper, lead, and zinc. They are found in veins and are formed by hydrothermal processes. Examples of sulphide ores are galena (PbS), chalcopyrite (CuFeS2), and sphalerite (ZnS). These ores are used in the extraction of metals.

Sulphate Ores:
Sulphate ores are compounds of sulphur with metals and oxygen. They are formed by weathering and oxidation of sulphide ores. Examples of sulphate ores are gypsum (CaSO4.2H2O), barite (BaSO4), and celestite (SrSO4). These ores are used in the production of cement, paints, and plastics.

Conclusion:
In conclusion, sulphur exists in earth’s crust in various forms such as elemental sulphur, sulphide ores, and sulphate ores. These forms have different properties and uses and are important resources for the chemical and mining industries.