Crystals and Minerals
A Mineral is a natural, mainly inorganic substance that occurs on Earth, with a chemical structure and a crystal formation.
It differs from a 'rock' in that a rock can be an aggregate of many minerals.
There are over 5,300 known minerals in the world, of which, silicon and its derivatives make up more than 90%.
Other mineral groups include sulphides, oxides, carbonates, halides, sulphates, phosphates and native elements.