Igneous Rock Identitification

Granite is an igneous rock that is coarsed-grained and light colored. It is mainly comprised of quartz and feldspars, along with mica and amphibole minerals. Granite is often times called the "best known" igneous rock because of its availibilty at the earth's surface. Most granite is plutonic, which means it forms deep within the earth. The mineral coloration of granite can vary. Colors include red, white, pink, grey, along with darker mineral coloration throughout the rock. A famous example of granite rock would be Mount Rushmore.

Rock Identitfication Lab

Limestone is a sedimentary rock that is generally composed of calcium carbonate (calcite). It is mainly formed in clear, warm, and shallow marine waters.

Hornblende can be either a calcium-iron-magnesium silicate, an aluminum-magnesium-iron silicate, or an iron-magnesium silicate.  This mineral makes up many igneous and metamorphic rocks.

Amethyst is a purple variation of quartz that gets its color from iron atoms in the crystal matrix.

Obsidian is an igneous rock that forms when molton rock material cools so fast that atoms are unable to form together in a crystalline structure.