By: Jordan Sloan
November 19, 2014
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 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 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.