Three Types of Rock

Look at these pictures of rocks. How are they different? How are they the same?

Igneous Rocks – ‘fire rocks’ Igneous rocks are made either underground or above ground.

Igneous Rocks – ‘fire rocks’ Underground: melted rock, called magma, cools slowly and becomes igneous rocks. These rocks are called intrusive Igneous rocks.

Igneous Rocks – ‘fire rocks’ Above ground: volcanoes erupt, bringing magma to the earth's surface, it is called lava. The lava cools and becomes igneous rocks. These rocks are called extrusive igneous rocks.

Igneous Rocks – ‘fire rocks’ Granite Pumice Basalt Obsidian

Sedimentary Rocks – ‘sandwich rocks’ For millions of years, rocks have been broken down (weathered) by wind and water into little pieces called sediment. They are called sandwich rocks because they form in layers.

Sedimentary Rock – ‘sandwich rocks’ These little bits of our earth are washed to the bottom of the rivers, lakes, and oceans where they settle (are deposited = deposition.

Sedimentary Rock – ‘sandwich rocks’ Many layers of small pieces of earth collect on top of each other in layers. These layers are pressed down more and more until the bottom layers slowly turn into hard rock.

Sedimentary Rock – ‘sandwich rocks’ Limestone Shale Sandstone

Metamorphic Rock – ‘changing rocks’ Metamorphic rocks are rocks that have "morphed" or changed into another kind of rock. These rocks were once igneous or sedimentary rocks.

Metamorphic Rock – ‘changing rock’ Millions of tons of heat and pressure have made these rocks change.

Metamorphic Rock – ‘changing rock’ Marble – from limestone Quartzite – from sandstone Slate – from shale