Host rocks for the deposits are limestone, shale, chert, intrusive bodies or metamorphosed volcanic and sedimentary rocks. Turquoise normally forms in narrow veins or small nodules along altered zones in host rock, but on rare occasions large slabs and nodules have been recovered.  You can easily identify these narrow veinlets in the Boulder Turquoise surrounded by the host rock. Also known as Royston Ribbon, the Boulder turquoise mine is located in northeast Nevada.  It was originally discovered in the 1970’s by a Shoshone sheep herder who stumbled upon a vein of turquoise on the hillside while tending sheep. The mine has been developed as an open cut and constitutes the mine’s workings. The mine is marked by extensive bulldozer cuts on the east side of a small rounded hill.  Production from the property has been small due to the limited amount of time allowed to mine due to the remote location and winter weather conditions combine to make Boulder Turquoise valued for both its beauty and rarity.