Intrusive igneous rocks

Igneous rock classification diagramZoom The Graven GraniteZoom Graven Granite detailZoomRocks are made of minerals – combinations of chemical elements that crystallize at specific temperatures and pressures. Igneous rocks are the most abundant type of rock on Earth. They are formed from the cooling of magma or lava and are classified according to their mineral composition, grain size and texture. Intrusive igneous rocks form when magma cools deep beneath Earth’s surface. They are coarse textured with large interlocking crystal grains. This is because the magma cools slowly, allowing time for big crystals to grow. The Graven Granite contains dark lenses of hornblende that appear to ‘float’ in the red granite matrix.