Where is Selenite Found in the US?

Selenite is a crystalline variety of the mineral gypsum that occurs in transparent crystals with a pearly luster. It is found in many parts of the United States, often associated with sedimentary deposits. Some of the notable selenite occurrences in the US include:

New Mexico

New Mexico has several significant selenite deposits, most notably at the Grand Quivira ruins in Torrance County. Large transparent selenite crystals up to a foot long have been found here. The crystals occur in beds of gypsum deposited in an ancient inland sea. Selenite is also found in the gypsum dunes of White Sands National Park and the nearby Lake Lucero lakebed.

Oklahoma

The great salt plains of northwestern Oklahoma contain abundant selenite crystals. They are excavated from the Flowerpot Formation, a gypsum unit deposited during the Permian Period. Bladed selenite crystals several inches long occur here. The Oklahoma selenite often exhibits hourglass inclusions of sand that make interesting patterns inside the crystals.

Texas

In West Texas, selenite crystals up to 20 inches long have been found in the Castile Formation in Culberson County. This unit was formed during the Permian Period when West Texas was covered by a shallow sea. Evaporation of the sea water led to the deposition of massive gypsum beds.

Utah

The Jurassic Carmel Formation in south-central Utah contains significant gypsum deposits. Large transparent selenite crystals are found in the area around Sevier Lake. These crystals can reach over a foot in length and display well-defined faces and striations.

Kansas

The Permian Blaine Formation of Kansas contains abundant beds of gypsum, including the selenite variety. Notable occurrences are found in Barber County where individual crystals up to 20 inches long have been found. The gypsum was deposited as Kansas was covered by a shallow inland sea during the Permian.

Nevada

In southern Nevada, selenite crystals up to 6 inches long occur in Clark County. They are found in clay beds within volcanic tuff dating to the Miocene Epoch. The selenite formed as ascending groundwater deposited dissolved gypsum.

California

In the Mojave Desert of California, selenite crystals occur in gypsum beds of Mio-Pliocene lake sediments. Notable deposits are found near Barstow in San Bernardino County. Individual crystals reach 3 inches in length.

Arkansas

In the Ouachita Mountains of Arkansas, selenite is found in Late Mississippian and Pennsylvanian aged strata. These ancient seabeds contain abundant gypsum that crystallized into selenite. Montgomery County contains some of the best specimens in the state.

These are some of the significant places where collectors can find selenite specimens in the United States. The mineral readily forms in evaporite settings as inland seas receded throughout geological history, leaving massive beds of gypsum. These gypsum deposits occasionally contain beautiful transparent crystals of the variety known as selenite that are treasured by rockhounds.