Name Also Known As Variations Distribution Complete Description  Complete Pictures Added Uinta Metamorhic Quartzite           Uinta Quartzite           Ukiah Valley Chert           Ullin Chert           Ultra Fossiliferous Chert           Unakite           Unga Island Wood           Union Marble           Uniontown Chert Waynesburg Chert         Unita Metamorphic Quartzite           Upland Chert           Upper Gull River Formation Chert           Upper Mercer Chert           Upper St. Louis Chert           Ursula Creek Chert           Utah Turquoise (varascite)           Utah Wonderstone           Utica Jewelstone           Utley Rhyolite Berlin Rhyolite         Uvalde Chert           Uwharrie Rhyolite Wolf Den Mountain Rhyolite