Description Each precast plaster and hand-painted rock is unique. Use Boulders for rocks at quarry sites, mining operations, road cuts and more. 22 rocks measuring 1 1/8" - 1 1/2" (2.85 cm - 3.81 cm) length x 3/4" - 1 3/4" (1.9 cm - 4.44 cm) height.