Rocks Rock

Dana Willson

What IS a rock?

Not everything you find in the ground is a rock. Some are minerals. Minerals are naturally occurring substances formed by geologic processes. A rock is a combination of several different minerals.

Are all rocks the same?

No!

Not all rocks are the same. There are three main types of rocks. These are sedimentary, igneous, and metamorphic. Sedimentary rocks

Sit and Wait

Sedimentary rocks are made by sitting and waiting. Pieces of shell collect together over time forming sediment. Eventually, the layers of sediment harden into rock. But, this type of rock is usually very soft and crumbly.

Pressure; pushing down on me

Metamorphic rocks are formed deep underground when a sedimentary rock experiences intense heat (but not enough to liquefy the rock) and pressure. Metamorphic rocks usually have ribbon like layers

The heat was hot

Igneous rocks are liquid rock that cooled and hardened. If the rock cooled underground, it probably cooled very slowly and came from magma. These rocks can have crystals or air pockets. If the rock cooled very fast, it probably cooled above ground and came from lava. These rocks are usually glass like