Sierra Salt n Pepper Boulders Central Valley California quarry producing a wide range of materials from rubble to large boulders. Materials are shipped bulked 18 to 24 tons throughout California. Smaller orders shipped on pallets anywhere requested. Sierra Salt n Pepper Boulders are a very hard quartz rock material that is a beautiful mixture of fall brown and gold colors. Rock material is available in 12 inch through 60 inch sizes, most commonly 24 to 36 inch.