mineral
Selenite
Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)
Hardness: 2 (can be scratched by a fingernail). Color: Colorless to white. Luster: Vitreous to pearly. Crystal Structure: Monoclinic, often tabular or bladed. Cleavage: Perfect (one direction). Specific Gravity: 2.3.
- Hardness
- 2 (can be scratched by a fingernail)
- Color
- Colorless to white
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 2 (can be scratched by a fingernail). Color: Colorless to white. Luster: Vitreous to pearly. Crystal Structure: Monoclinic, often tabular or bladed. Cleavage: Perfect (one direction). Specific Gravity: 2.3.
Formation & geological history
Formed as an evaporite mineral in sedimentary environments such as marine basins or saline lakes through the evaporation of water. Deposits can range from millions of years old to relatively modern formations in arid regions.
Uses & applications
Used in the production of plaster of Paris, wallboard (drywall), soil fertilizer, and as a filler in paper and paints. Transparent varieties like the one pictured are popular for metaphysical use and ornamental collecting.
Geological facts
The famous Naica Mine in Mexico contains selenite crystals over 30 feet long. Selenite is extremely water-soluble; if left in water, it will eventually dissolve. It is the defining mineral for hardness level 2 on the Mohs scale.
Field identification & locations
Identify by its extreme softness (scratches with a fingernail) and its tendency to peel into thin sheets or break along flat cleavage planes. Commonly found in desert regions, ancient seabed deposits, and near hot springs.
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sedimentary
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Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
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