Oregon Moss Rock and Boulders Granite or Sandstone Oregon quarries or rock wranglers harvesting surface select stone materials with lichens and moss growing on the stone. Stone materials include patio flagstone, large slabs, and boulders. Stone materials are shipped bulked on flatbeds in amounts of 18 to 24 tons throughout Northern California and Nevada, Idaho, Oregon and Washington. These slabs and boulders are harvested from the surface of the bedrock and grasslands of Oregon. Typically this rock material is harvest from cattle range lands, where harvesting the stone improves the grazing quality of the range land. This material has been baked in the sun of Colorado summers for hundreds of years, if not longer, and then covered most winters in snow. The result is usually a very grey rock with the additional benefit of lichens or moss growing and covering in full or in patches on the rock.