Extrusive igneous rocks

Extrusive igneous rocks erupt on the surface, where they cool quickly to form tiny crystals

Some cool so quickly that they form an amorphous glass.

These rocks include andesite (feldspar, pyroxene, jade, spodumene, hiddenite, kunzite), basalt, dacite (quartz, labradorite, feldspar), obsidian, pumice and rhyolite.