CHALCOPYRITE

A member of the sulphide group and an important source of copper. It is a brassy yellow colour and resembles pyrite. It is often know as copper pyrite.

About 30% of it's mass is copper and it is widely used in industry.

It occurs in igneous rocks and is abundant in Cornwall, UK.

GRANITE

One of the most widespread minerals. It is an intrusive igneous rock formed mainly of quartz, mica and feldspar (most deposits contain 20-35% quartz).

It has coarse grains and is white, pink and grey.

It forms at great depths and is exposed to the surface when less resistant rocks above it are eroded.

It may be found extensively in Cornwall and Devon (England) and Scotland.