Where is Selenite found?
Gypsum (fibrous variety)
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Open the appSelenite occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Selenite
Naica Mine, Chihuahua, Mexico
Famous for its 'Cave of Crystals' (Cueva de los Cristales), containing some of the largest selenite crystals ever found, up to 12 meters long.
Great Salt Plains State Park, Oklahoma, USA
Known for its unique 'hourglass' selenite crystals, which visitors can dig for.
Coober Pedy, South Australia
While famous for opal, selenite is also found in the sedimentary layers here.
Bologna, Emilia-Romagna, Italy
Historically significant for its transparent selenite crystals, known as 'Pietra di Bologna'.
Various desert regions worldwide
Including parts of the Sahara, Atacama, and American Southwest, where evaporitic conditions lead to gypsum formation.
Collecting tips
- Look for Evaporite Environments. Focus on areas that were once or are currently saline lakes, playas, or shallow marine basins in arid climates. Look for associated minerals like halite, anhydrite, and other sulfates.
- Check Cave Systems. Selenite can form spectacular crystal growths in caves, often as 'gypsum flowers' or large, clear crystals, particularly in limestone caves.
- Examine Sedimentary Layers. Selenite often occurs in distinct layers within sedimentary rock sequences, sometimes interbedded with shales, limestones, or sandstones.
- Test Hardness. Its extreme softness (Mohs 2) is a key identifier. It can be easily scratched with a fingernail, which distinguishes it from harder minerals like quartz or calcite.
- Observe Cleavage. The perfect cleavage into thin, flexible sheets is a very strong diagnostic feature for selenite.
Quick Check
- Color:
- Colorless to white, transparent
- Luster:
- Vitreous to pearly
- Streak:
- White
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