Characteristics of igneous rocks :-
1. Normally contains no fossils.
2. Usually has no layering
3. Rarely reacts with acids.
4. Usually made of two or more minerals.
5. May be light or dark coloured.
6. Usually made of mineral crystals of different sizes.
7. Sometimes has openings or glass fibers.
8. May be fine-grained or glassy (extrusive).