In geology, a rock is a naiturally occurrin solit aggregate o ane or mair meenerals or meeneraloids. For ensaumple, granite, a common rock, is a combination of the meenerals quartz, feldspar an biotite. The Yird's ooter solit layer, the lithosphere, is made o rock.
Rock haes been uised bi humankynd ootthrou history. The meenerals an metals in rocks hae been essential tae human ceevilisation.
Three major groups o rocks are defined: igneous, sedimentar, an metamorphic. The scienteefic study o rocks is cried petrology, that is an essential component o geology.