Rocks are made up of one or more minerals. Although different rocks can contain the same minerals, they are sorted into different types of rocks depending on how they were formed.
Metamorphic rocks form when existing rocks are exposed to heat and pressure deep within the Earth’s surface. That’s a pretty neat way of understanding different types of rocks!
Examples of metamorphic rocks are marble and slate. There are many more with some really weird names like anthracite, quartzite, granulite, gneiss and schist.
There are three types of rocks: igneous, sedimentary and of course metamorphic rocks.
This type of rock is formed under extreme pressure and heat over quite a long time.
Metamorphic rocks are called this name as they always start out as another rock. Metamorphic is a word that literally means to change from one thing to another. There you go…now you know!
When slate forms, some of the clay from the original rock is replaced by the mineral called mica.
During the stage of changing, called contact metamorphism, broken down pieces of rock near the Earth’s surface is changed by magma.
During regional metamorphism, another stage of changing, rocks buried deep down in the Earth are changed by magma chambers.
Even though the rock gets really, really hot and is under a whole heap of pressure it doesn’t melt. Wow, that’s one strong rock. If it did melt, that would mean that either igneous or sedimentary rocks would form.
Igneous Rocks – these are formed through the cooling and then solidifying (becoming solid) of magma or lava.
Sedimentary Rocks – these are formed by sediment that is deposited over time, usually as layers at the bottom of lakes and oceans.
Foliated – this means that something is made up of thin sheets.
Durable – means that something is quite strong.