Different Types of Rock

There are [blank_start]3[blank_end] types of rock

Igneous rocks are formed by [blank_start]magma[blank_end] (melted underground rock) which is pushed up to the [blank_start]crust[blank_end] and often out [blank_start]volcanoes[blank_end]

Igneous rocks contain various [blank_start]minerals[blank_end] in randomly arranged [blank_start]interlocking crystals[blank_end]. The [blank_start]size[blank_end] and [blank_start]texture[blank_end] of the crystals depend on speed of cooling

There are 2 types of igenous rock- [blank_start]extrusive[blank_end] and [blank_start]intrusive[blank_end]

Extrusive igneous rocks cool [blank_start]quickly[blank_end] [blank_start]above[blank_end] ground

Intrusive igneous rocks cool [blank_start]slowly[blank_end] [blank_start]below[blank_end] ground

Igneous rocks don't form [blank_start]fossils[blank_end] as any [blank_start]fossils[blank_end] wil have melted to form [blank_start]magma[blank_end] in the original rock

Sedimentary rocks are formed by layers of [blank_start]sediment[blank_end], which are [blank_start]rock fragments[blank_end] that are deposited

To form sedimentary rocks, over time the [blank_start]layers[blank_end] are [blank_start]cemented[blank_end] together by [blank_start]minerals[blank_end] that act as glue

To form sedimentary rocks, the weight of the [blank_start]sediments[blank_end] on top squashes the [blank_start]sediments[blank_end] at the botoom. This is called [blank_start]compaction[blank_end]

[blank_start]Fossils[blank_end] can form in the sediments. this is the long dead remains of animals and plants

Metamorphic rocks are made by the result of [blank_start]heat[blank_end] and [blank_start]increased[blank_end] pressure acting on existing [blank_start]rocks[blank_end] over a [blank_start]long[blank_end] period of time

Metamorphic rocks may have tiny [blank_start]crystals[blank_end] and some have [blank_start]layers[blank_end]

Metamorphic rocks are always made from [blank_start]interlocking[blank_end] crystals

Metamorphic rocks usually have different properties to the [blank_start]rocks[blank_end] from which [blank_start]they were made from[blank_end]

Metamorphic rocks are never made from [blank_start]molten[blank_end] rock

Metamorphic rocks rarely contain [blank_start]fossils[blank_end]. The don't normally usrvive the [blank_start]heat[blank_end] and [blank_start]pressure[blank_end]

Metamorphic rocks can be heated up by the movement of [blank_start]tectonic plates[blank_end] or [blank_start]magma[blank_end]

The higher temperature and pressure of rock when formed, the crystal size [blank_start]increase[blank_end] and the thickness of layers [blank_start]increase[blank_end]