Desert bighorn sheep establish two desert areas in southwestern Arizona to help preserve the desert bighorn sheep: Cabeza Prieta National Wildlife Refuge and the Kofa National Wildlife Refuge. In 1941, the San Andres National Wildlife Refuge in New Mexico was added. Desert bighorn sheep populations have trended upward since the 1960s when their population was estimated at 6,700-8,100. The upward trend was caused by conservation measures, including habitat preservation. In 1980, desert bighorn sheep populations were estimated at 8,415-9,040. A state-by-state survey was conducted a few years later and estimated the overall US desert bighorn sheep population at 15,980. The 1993 estimate of
Desert rose (crystal) as the official rock of the US state of Oklahoma in 1968. The average size of rose rocks are anywhere from to in diameter. The largest recorded by the Oklahoma Geological Survey was across and high, weighing . Clusters of rose rocks up to tall and weighing more than have been found. Desert rose (crystal) Desert rose is the colloquial name given to rose-like formations of crystal clusters of gypsum or baryte which include abundant sand grains. The 'petals' are crystals flattened on the "c" crystallographic axis, fanning open in radiating flattened crystal clusters. The rosette crystal habit tends to