Examples of Various Rock Types

Granite

Igneous rock Contains large crystals Hard rock Cooled slowly under the surface of the Earth (intrustive) Composed mainly of quartz Found mainly in Dartmoor, southern Devon, England.

Basalt

Igneous rock Contains non-visible crystals Hard rock Cooled quickly on the surface of the earth (extrusive) Composed mainly of plagioclase and pyroxene minerals Found mainly in northern Co. Antrim, most famously at the Giant's Causeway

Chalk

Sedimentary rock Composed of calcium carbonate Porous Susceptible to weathering by solution Primarily found in the South Downs

Sandstone

Sedimentary rock Composed of compressed layers of sand Hard rock Commonly used for paving Found at Baggy Point, Devon

Schist

Metamorphic Rock Usually forms on a continental side of a convergent plate boundary where sedimentary rocks have been subjected to pressure and heat. Formed mainly from shale Contain visible crystals Can be found in South Devon

Slate

Metamorphic rock Composed of shale Extremely fine-grained Typically used in building Commonly found in Snowdonia