mineral
Clear gypsum (selenite)
Gypsum, CaSO₄·2H₂O; selenite is its transparent to translucent crystalline variety
AI-generated identification · may be incorrectColorless to white, vitreous to pearly luster, and perfect cleavage; Mohs hardness 2, monoclinic crystal system, specific gravity about 2.3. The specimen’s soft, layered-looking cleavage surfaces are consistent with gypsum.
Identified More mineral →
Explore Clear gypsum (selenite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Colorless to white, vitreous to pearly luster, and perfect cleavage; Mohs hardness 2, monoclinic crystal system, specific gravity about 2.3. The specimen’s soft, layered-looking cleavage surfaces are consistent with gypsum.
Formation & geological history
Forms when calcium- and sulfate-rich water evaporates in sedimentary basins, or through hydration of anhydrite; deposits range from geologically recent to hundreds of millions of years old.
Uses & applications
Gypsum is used in drywall, plaster, cement, and agriculture; clear selenite is collected and sometimes carved into decorative objects, but is too soft for most jewelry.
Geological facts
Gypsum can be scratched with a fingernail, a useful field clue; selenite is the mineral name, not a separate chemical species.
Field identification & locations
Common in evaporite deposits worldwide, including the United States, Mexico, and Spain. Confirm softness and cleavage; avoid water and abrasion because gypsum is easily damaged.
More like this
Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous