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Dioptase

Emerald-green copper silicate that fooled Kazakh merchants and Russian tsars.

Family
Dioptase
Formula
CuSiO₃·H₂O
Mohs
5
System
Trigonal

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Science

Dioptase forms in the oxidised zone of copper deposits as short, brilliant green prisms. Its cleavage is so distinct that Haüy named it in 1797 from dia and optos, 'seeing through', because the cleavage planes are visible inside. Too soft and fragile for rings, it is prized as a specimen.

Mineral
Dioptase
Formula
CuSiO₃·H₂O
Crystal system
Trigonal
Mohs hardness
5
Specific gravity
3.28 to 3.35
Refractive index
1.644 to 1.709
Lustre
Vitreous
Colours
Emerald green, Blue-green

Composition

CuSiO₃·H₂O. Made of Copper, Silicon, Oxygen, Hydrogen.

in formula

Origin

  • Namibia
    Tsumeb
  • Kazakhstan
    Altyn-Tyube, first find
  • Democratic Republic of the Congo
  • Chile
  • United States
    Arizona
  • Peru

Filled dots are primary sources

Rarity

Rare
4 of 5

Crystals are small and brittle; specimens from Tsumeb and Altyn-Tyube are collector pieces and it is rarely cut.

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

Hardness

Dioptase sits at 5 on the Mohs scale. Glass and a knife blade are about as hard; it wears well with care.

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

  • Heart

Element

  • Water

Zodiac

  • Sagittarius
  • Scorpio

Planets

  • Venus

Properties

  • Heart healing
  • Forgiveness
  • Abundance
  • Living in the present

Lore

In the 1780s merchants brought it from Kazakhstan to Russia as emerald; Catherine the Great's court was briefly excited until analysis found copper. The locality, Altyn-Tyube, means golden hill.

Modern practice treats it as the most direct heart stone in the copper group.

  • Named
    1797 by René Just Haüy, founder of crystallography.
  • Fragile
    Perfect cleavage; never ultrasonic-clean it.