Granite is a common intrusive igneous rock. Lava cools very quickly on the earth's surface because it is suddenly exposed to cool temperatures. Crystals often do not have time to develop in the rock that forms. Rock that forms without crystals on the earth's surface has a fine texture, and is called extrusive igneous rock. The most common rock formed from lava is called basalt.
Igneous rock contains metallic minerals such as nickel, copper, gold and silver.
The Canadian Shield is partially composed of igenous rock, and consequently, contains large amounts of these minerals. The Coast Mountains of BC are also made of igneous rock and they too contain metallic minerals. Sedimentary Rock Formed from igneous rock that was eroded by wind, water and ice. Tiny pieces of igneous rock were eroded and carried by running water into prehistoric seas. Over millions of years, these sediments were deposited in horizontal layers thousands of metres thick.