mineral—A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystalline structure, color, and hardness. Minerals are chemical compounds.
rock—Relatively hard, naturally formed mineral or petrified matter; stone; a naturally formed aggregate of mineral matter constituting a significant part of the earth's crust. Rocks consist of one or more minerals.
The mineral composition of a rock reflects the physical environment and geologic history where a rock formed.