There are many ways of classifying rocks, but one of the most common is by their appearance and physical properties.

A rock can be classified in terms of its colour and texture, but it can also be classified by its mineral content. This is because each mineral has its own chemical composition and physical properties, so it will react differently when exposed to different conditions.

The following are some of the characteristics that are used to classify rocks:

Texture – this is how a rock feels when you pick it up or break it. It can be described as hard (like granite), soft (like sandstone) or somewhere in between (like limestone).

Luster – this is how shiny a rock is when light hits it. It can be described as dull (like granite), shiny (like quartzite) or somewhere in between (like limestone).

Colour – this refers to the colour of a rock when light shines on it at different angles. The best way to see this is with olivine crystals which have a beautiful blue colour when viewed from certain angles but appear black from others.

Last modified: September 7, 2022