The Glass Mountains or Gloss Hills are a series of mesas and buttes that extend from the Permian red beds of the Blaine Escarpment of northwestern Oklahoma in Major County. The mountains rise 150 feet (46 m) to 200 feet (61 m) above the surface of the plains. The highest elevation in the formation is about 1,600 feet (490 m) above sea level. The Glass Mountains stretch west along US Highway 412 from Orienta south of the Cimarron River. The name comes from the sparkling selenite crystals on the slopes and tops of the mesas. The first American explorers referred to them as the "Shining Mountains," when they saw the formation in 1821.
The region became part of the Cherokee Strip during the 19th Century.In 1891, botanist George Walter Stevens, started collecting specimens in the Glass Mountains domain for his dissertation. The University of Oklahoma Bebb Herbarium holds 4,500 samples that Stevens collected statewide. Two cacti he may have collected in the Glass Mountains area are Echinocereus caespitosus and Opuntia phaecantha.
In 1875, a transcription error by a mapmaker resulted in the name Gloss Mountains which is still a somewhat common name for the mountains.
The state of Oklahoma operates the 640 acres (260 ha) Glass (Gloss) Mountain State Park, 6 miles (9.7 km) west of Orienta on a mesa along Highway 412. The park allows climbers to hike to the top of the mesa via a path and stairs. Picnic tables and an informational kiosk have been installed, and a pond known as Rattlesnake Lake is nearby.
- Adams, George Irving. 1904. Gypsum deposits in the United States. U.S. Geological Survey, Bulletin 223, 129 pp. (Plate 15-A)
- McPhail, Melanie L. and Richard A. Marston. Encyclopedia of Oklahoma History and Culture. "Glass Mountains." Retrieved March 5, 2015.
- Burchardt, Bill. 1970. The Glass Mountains: Our Treasure in Trust. Oklahoma Today 21(1):29-38.
- Encyclopedia of Oklahoma History and Culture - Glass Mountains
- Oklahoma Digital Maps: Digital Collections of Oklahoma and Indian Territory