rock rocks Hard mineral material igneous rock igneous rocks Rock solidified from volcanic lava or magma metamorphic rock metamorphic rocks Rock that has undergone transformation by heat, pressure or other natural agencies sedimentary rock sedimentary rocks Rock formed from sediment deposited by water or wind basalt lapis basanites Dark fine grained volcanic rock composed largely of plagioclase with pyroxene and olivine granite moorstone Hard crystalline igneous rock consisting mainly of quartz, mica and felspar marble Hard crystalline metamorphic form of limestone slate slatestone Fine grained metamorphic rock easily split into smooth, flat plates limestone Hard sedimentary rock composed mainly of calcium carbonate sandstone arenaceous rock Sedimentary rock consisting of sand or quartz grains cemented together