Igneous Rocks:
Igneous rocks form when magma (molten material) cools and solidifies. No matter what kind of rock you started with, once it melts and then solidifies it is now igneous rock (look at the Rock Cycle diagram at the top of page 6).
Igneous rocks may be made of one or more different minerals. It is important to understand that if a questions asks about igneous 'rocks' the answer must be one of the rock names from the upper section of the 'Scheme for Igneous Rock Identification'.
If a question refers to 'minerals' then choose one or more minerals from the 'mineral composition' section at the bottom of the page.
Rocks are at the top........... The minerals that are in those rocks are at the bottom.
Igneous rock are classified according to:
1) Crystal size (texture) and
2) Mineral composition