Rocks

The solid mineral material forming part of the surface ofthe earth and other planets.

Igneous Rocks

“Fire Rocks”

Volcano

Volcanoes may be active, dormant, or extinct.

Basalt

Extrusive, dark, most common type of rock in theEarth’s crust, and makes up most of ocean floor.

Granite

Intrusive (formed by slow cooling of magma underground). It is often used

for building.

Obsidian

Formed when lava cools quickly above ground.It is black glass with sharp edges and is used for making cutting tools and arrowheads.

Pumice

Cooled quickly allowing air bubbles to form.Light enough to float on water.

Rhyolite

Scoria

“Lava Rock”, lightweight extrusive rock with large,gas bubbles. It is usually red or dark in color.

Sedimentary Rocks

“Layered rocks”

Breccia

Made up of angular pieces cemented togetherby minerals.

Conglomorate

Rounded pieces cemented together by minerals.

Limestone

Made up from the mineral calcite which came from bedsof evaporated seas and lakes and sea animal shells.

Sandstone

Composed of sand-sized minerals or rock grains.

Shale

A fine-grained rock made up of mud that is a mix of

clay and salt minerals.

Travertine

Hematite

Coal

The actual remains of dead plants from long ago.

Fossils

Metamorphic Rocks

“Changed Rocks”

Gneiss

Used to be granite, but heat and pressure turned it into gneiss. It as bands of gray and white.

Hornfel

Marble

Used to be limestone until heat and pressure turned it intothe metamorphic rock called marble.

Quartzite

Was once sandstone and then heat and pressure transformedit into the metamorphic rock Quartzite.

Schist

Used to be Basalt. Heat and pressure changed it intothe Metamorphic rock, Schist.

Slate

Used to be shale. Heat and pressure changedit into slate.

Metamorphic “Changed”

Sandstone ------------------ QuartziteLimestone ------------------ MarbleGranite ------------------ GneissBasalt ------------------ SchistShale ------------------ Slate