- a plaster compound creating the trompe l'oeil appearance of rock.
- 1985, Anne Tyler, The Accidental Tourist, Knopf, ISBN 039454689X, page 199,
- He turned into Singleton and found a block of row houses that gave a sense of having been skimped on. ... Most were covered in formstone, but the bricks of Number 16 had been painted a rubbery maroon.