Rocks

By: Jordan Sloan
Science 7-2
November 19, 2014

Igneous

An Igneous Rock is a rock that involves volcanic processes.  It is made when a volcano erupts.

Granite- A very hard igneous rock that is mainly made of quartz, mica, and feldspar.  It is often used as building stone.

Obsidian- A hard, dark, glasslike, volcanic rock formed by solidfication of lava.

Scoria- A cindery, basaltic lava, that has a frothy texture.

Pumice- A light volcanic rock that forms when a gas-rich froth of glassy lava solidfies rapidly.

Gabbro- A dark, coarse-grained rock with crystalline texture.  Mainly made up of pyroxene, plagioclase, felspar, and olivine.

Metamorphic

Metamorphic Rock is a denoting rock that is made by heat and pressure.

Gneiss- A rock with a banded structure and coarse-grained.  It is mainly made of feldspar, quartz , and mica.

Marble- A crystalline form of limestone that is used to make sculptures.

Soapstone- A soft rock made mainly of talc.

Novaculite- A hard rock, resembling chert. It is made mainly of  mircocrystalline quartz.

Schist- A coarse-grained rock that has layers of different minerals.

Sedimentary

Sedimentary Rock is something that has formed from sediment and deposited by water or air.

Limestone- A hard rock that is made mainly out of Calcium Carbonate.  It is used to build material that has cement involved.

Breccia- Made out of mineral cement that binds the rock together.

Coal- Is a fossil fuel,  Made out of strata and altered by heat over many years.

Sandstone- A rock made mainly of sand or quartz grains that is cemented together.

Flint- A gray rock made mainly of chert.

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