Igneous rocks are formed from molten material called magma that comes from deep inside the Earth. Sometimes this material cools slowly under the surface, but sometimes it explodes out from a volcano as liquid lava. Igneous rocks are also called volcanic rocks.
At one time the whole of the Earth’s crust was formed from igneous rocks. It has taken millions of years for the other types to be formed. The changing of rocks from one form into another is called the rock cycle.
- Moon rock, meteorites, comets
By the way, don’t worry if you can’t pronounce some of these words properly - most of Quarryville’s workers have the same problem!
Ignis is the Latin word for fire.
Geologists classify rocks into three types according to the different ways in which they’re formed:
- Igneous (pronounced ig-knee-us)
- Metamorphic (met-a-more-fic)
- Sedimentary (sed-ee-ment-ary)