Fire Rocks

Igneous rock is formed by cooling magma or lava and it is formed above ground and is formed below the earths surface. Igneous rocks are also known as "Fire Rocks" Because they are formed from molten rock. Granite, scoria, pumice and obsidian are all examples of Igneous rock. Granite is formed above ground when lava is exposed and cools rapidly which forms large crystals in the rock. These rocks are usually light in colour. Scoria, pumice and obsidian are formed when magma is trapped and cools slowly which forms little crystals and these rocks are usually stronger and darker in colour than the rocks formed above ground.