- Igneous rocks have a crystalline nature. This is why they glitter in the sun or look glassy in appearance. The crystalline nature of igneous rocks shows that they contain crystals,
- Igneous rocks are usually very resistant to erosion and other climatic elements.
- They are very hard and contain no animal or plant remains (fossils).
- Igneous rocks do not occur in layers and as such are regarded as non-stratified rocks.
- Some Igneous rocks have little holes on the surface e.g. pumice rock.
- Igneous rocks may be dark, grey or brown in colour.
- Some igneous rocks may be heavy or massive.