Explanation

Three rock types based on formation. Igneous: from cooled magma/lava. Intrusive (granite) cools slowly underground = large crystals. Extrusive (basalt) cools quickly = small crystals.

Sedimentary: from compressed sediments. Clastic (sandstone, shale) from rock fragments. Organic (coal, limestone) from organisms. Chemical (rock salt) from evaporation.

Metamorphic: changed by heat/pressure. Limestone becomes marble, shale becomes slate, granite becomes gneiss. The rock cycle connects all three types.