Rocks and Minerals
Rocks are made of one or more minerals.
- Minerals can be identified by properties such as colour, hardness, and lustre.
- Rocks form in three main ways — igneous (from cooled magma), sedimentary (from layers pressed together), and metamorphic (changed by heat and pressure).
- The rock cycle slowly turns one type of rock into another.
Testing a mineral's hardness — whether it scratches or is scratched — is one clue to identifying it.