Rock-salt
ROCK'-SALT, noun Fossil or mineral salt; salt dug from the earth; muriate of soda. But in America, this name is sometimes given to salt that comes in large crystals from the West Indies, which salt is formed by evaporation from sea water, in large basons or cavities, on the isles. Hexahedral rock-salt occurs foliated and fibrous.
ROCK'-WOOD, noun Ligniform asbestus.
ROCK'-WORK, noun
1. Stones fixed in mortar in imitation of the asperities of rocks, forming a wall.
2. A natural wall of rock.