It is the intrusive igneous equivalent of the extrusive igneous dacite. The extrusive igneous rock equivalent of granite is rhyolite. They consist of metamorphosed graywacke, argillite, tuff, mafic igneous extrusive flows, and carbonate rock. Cinders are extrusive igneous rocks; they are fragments of solidified lava. Composite or stratovolcanoes often have andesitic magma and typically form the extrusive rock andesite. Andesite can be considered as the extrusive equivalent of plutonic diorite. The extrusive volcanic equivalent rock type is andesite. Other examples of extrusive rocks are rhyolite and andesite. Basalts are extrusive igneous rocks derived from the partial melting of the upper mantle. The name Sidian is derived from Obsidian, an extrusive igneous rock. Because volcanic bombs cool after they leave the volcano, they are extrusive igneous rocks. Zhokhov Island consists of extrusive basalt lava flows and tuffs. They show structures intermediate between those of extrusive and plutonic rocks. Basalt is a dark colored extrusive volcanic rock. Dolerite dykes intruded the extrusive volcanic rocks around 563 million years ago.