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Selenite

Also Gypsum, Satin spar

Crystalline gypsum, soft enough to scratch with a fingernail, grown to eleven metres.

Family
Gypsum
Formula
CaSO₄·2H₂O
Mohs
2
System
Monoclinic

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Science

Selenite is transparent gypsum in blades and 'fishtail' twins; satin spar is the fibrous form sold as wands. It grows from evaporating water. In the Naica mine, Mexico, crystals up to eleven metres grew in a flooded cave at 58 °C over half a million years, found in 2000 when the water was pumped out.

Mineral
Gypsum (variety)
Formula
CaSO₄·2H₂O
Crystal system
Monoclinic
Mohs hardness
2
Specific gravity
2.32
Refractive index
1.520 to 1.530
Lustre
Pearly to silky
Colours
Colourless, White, Peach

Composition

CaSO₄·2H₂O. Made of Calcium, Sulfur, Oxygen, Hydrogen.

in formula

Origin

  • Mexico
    Naica, Cave of the Crystals
  • Morocco
    satin spar wands
  • United States
    Utah, Oklahoma
  • Australia
  • Brazil

Filled dots are primary sources

Rarity

Abundant
1 of 5

Gypsum is everywhere; plaster is made from it. Clear selenite blades and satin spar are cheap.

  1. 1 Abundant
  2. 2 Common
  3. 3 Uncommon
  4. 4 Rare
  5. 5 Exceptional

Hardness

Selenite sits at 2 on the Mohs scale. A steel knife will scratch it; it suits pendants and display more than rings.

Fingernail
Copper coin
Knife, glass
Steel file
1
2
3
4
5
6
7
8
9
10

Energy

Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.

Chakras

  • Crown

Element

  • Air

Zodiac

  • Taurus
  • Cancer

Planets

  • Moon

Properties

  • Cleansing
  • Clarity
  • Peace
  • Charging other stones

Lore

Named for Selene, the moon goddess, for its pale glow. Thin sheets glazed windows in ancient Rome and medieval churches, where it is still called 'Mary's glass'.

In modern practice it is the stone that cleanses everything else, placed under other crystals; it dissolves in water and must be kept dry.

  • Naica
    The largest crystals on Earth, in a cave now re-flooded.
  • Water
    Slightly soluble; never soak selenite.