Sedimentary rocks form when sediment, made of small bits of rock, is pressed and cemented together. They often form in flat layers.

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​Sedimentary Rock

(sedimentary = pressure)

​sandstone

​limestone

shale

Metamorphic rocks form when intense heat and pressure are applied to existing rock. The new rocks can be very dense and have bands or stripes.

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metamorphic Rock

(metamorphic = heat & pressure)

​marble

​diamond

gneiss

Igneous rocks form from the cooling of melted rock. They may form on or near the surface or deep underground.

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igneous Rock

(igneous = extreme heat)

​pumice

granite

obsidian