causing them to change into another type of rock. They are usually resistant to weathering and erosion and are therefore very hard-wearing. Examples of metamorphic rocks include marble ...

Metamorphic rocks are the third main classification. These started out as other types of rock but were changed by high heat and pressure. In this article, we'll list 30 types of rock with pictures ...

A compound is a substance that contains two or more elements close elementA pure substance that is made from only one type of atom ... Chalk is a sedimentary rock. Metamorphic rocks are formed ...