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Where is Cat's Eye Selenite found?

Selenite (fibrous gypsum variety)

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Cat's Eye Selenite 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 Cat's Eye Selenite

Naica Mine, Chihuahua, Mexico

Famous for its giant selenite crystals, including fibrous varieties, found in hydrothermal caves.

Oklahoma, USA

Known for its 'rose rock' formations, which are barite roses, but also has significant gypsum deposits, including fibrous forms.

Utah, USA

Various evaporite deposits yield gypsum, including fibrous varieties.

Australia

Extensive gypsum deposits in arid regions, often containing fibrous forms.

Morocco

A significant source of various gypsum forms, including fibrous selenite.

Collecting tips

  1. Look in Evaporite Deposits. Search in areas with ancient or modern evaporite formations, such as dried lake beds, sabkhas, or sedimentary layers associated with past marine environments.
  2. Check Cave Systems. Selenite, including fibrous varieties, can form in caves where sulfate-rich waters drip or seep, leading to crystal growth.
  3. Examine Sedimentary Rocks. Look for veins or seams within shales, limestones, or sandstones, particularly in arid regions.
  4. Test for Softness. Gypsum is very soft (Mohs 2). It can be easily scratched with a fingernail, which helps distinguish it from harder minerals like quartz (Tiger's Eye).
  5. Observe Chatoyancy. Rotate the specimen under a direct light source to observe the characteristic 'cat's eye' effect, a silky band of light that moves across the surface.

Quick Check

Color:
White, colorless, pale yellow/brown
Luster:
Silky to pearly, chatoyant
Streak:
White

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