(Encyclopedia) rock, aggregation of solid matter composed of one or more of the minerals forming the earth's crust. The scientific study of rocks is called petrology. Rocks… Burly, snarly and yet lovable, Dwayne "The Rock" Johnson turned his pro wrestling popularity into an acting career with the lead role in The Scorpion King in 2002. The son of pro wrestler Rocky… (Encyclopedia) igneous rock: see rock . (Encyclopedia) metamorphic rocks: see rock . (Encyclopedia) sedimentary rock: see rock ; sediment . (Encyclopedia) rock and roll: see rock music . (Encyclopedia) rock garden, garden planned around natural rock formations or rocks artificially arranged to simulate natural (often mountainous) conditions. The concept of rock gardens… (Encyclopedia) rock crystal: see quartz . (Encyclopedia) rock rabbit: see pika . (Encyclopedia) rock salt: see sodium chloride .