ore deposits tend to occur in nearly vertical mineralized faults or fault zones in the rhyolite. Most of the lodes in the Bullfrog Hills are not simple veins but rather fissure zones with many stringers of vein material. Geography and climate Rhyolite is at the northern end of the Amargosa Desert in Nye County in the U.S. state of Nevada. Nestled in the Bullfrog Hills, about northwest of Las Vegas, it is about south of Goldfield, and south of Tonopah. Roughly to the east lie Beatty and the Amargosa River. To the west, roughly from Rhyolite, the Funeral and Grapevine Mountains of the Amargosa Range rise between the Amargosa Desert in Nevada and Death Valley in California. State Route 374, passing about south of Rhyolite, links Beatty to Death Valley via Daylight Pass. Rhyolite is about west of Yucca Mountain and the proposed Yucca Mountain nuclear waste repository, which is adjacent to the Nevada Test Site. Bordered on three sides by ridges but open to the south, the ghost town is at above sea level. The high points of the ridges are Ladd Mountain to the east, Sutherland Mountain to the west, and Busch Peak to the north. Sawtooth Mountain, the highest point in the Bullfrog Hills, rises to above sea level about northwest of Rhyolite. The hills form a barrier between the Amargosa Desert and Sarcobatus Flat to the north. Most of the primary mining communities in the Beatty–Rhyolite area during the gold-rush boom of 1904–08 were either in or on the edge of the Bullfrog Hills. Of these and many smaller towns and camps in the Bullfrog district, only Beatty survived as a populated place. Prior to its demise, the rival town of Bullfrog lay about southwest of Rhyolite, and the Montgomery Shoshone Mine was on the north side of Montgomery Mountain, about northeast of Rhyolite. Nevada's main climatic features are bright sunshine, low annual precipitation, heavy snowfall in the higher mountains, clean, dry air, and large daily temperature ranges. Strong surface heating occurs by day and rapid cooling by night, and usually even the hottest days have cool nights. The average percentage of possible sunshine in southern Nevada is more than 80 percent. Sunshine and low humidity in this region account for an average evaporation, as measured in evaporation pans, of more than of water a year. Beatty, about lower in elevation than Rhyolite, receives only about