Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals. Some cool so quickly that they form an amorphous glass. These rocks include: andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff.

Another characteristic used to help identify igneous rocks is its color. Igneous rocks are classified based on only 4 colors: mafic, ultramafic, felsic, and intermediate. Very light in color, a bunch of quartz, potassium feldspar, very few dark minerals found. These are your white and pink colored igneous rocks.

The Earth is made up of three rock types – Igneous, Metamorphic, and Sedimentary. Igneous rocks get their name from the Latin word “ignis”, which means fire. They are indeed born from fire or from the magma of the Earth.

Extrusive rock

• Igneous rock.
• Pumice.
• Basalt.
• Perlite.
• Trachyte.
• Obsidian.
• Rhyolite.
• Phonolite.

basalt

Granite is a light-colored igneous rock with grains large enough to be visible with the unaided eye. It forms from the slow crystallization of magma below Earth’s surface. This mineral composition usually gives granite a red, pink, gray, or white color with dark mineral grains visible throughout the rock.

When magma never reaches the surface and cools to form intrusions (dykes, sills etc) the resulting rocks are called plutonic. Depending on their silica content, they are called (in ascending order of silica content) gabbro, diorite, granite and pegmatite. By quantity, these are the by far most common rock types.

Igneous rocks which cool and solidify deep in the earths crust are called plutonic rocks. Examples of plutonic rocks are granite, gabbro, and granodiorite.

plutonic igneous rock having visibly crystalline texture; generally composed of feldspar and mica and quartz. type of: igneous rock. rock formed by the solidification of molten magma.