Lapidarium
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Smoky Quartz

Quartz darkened by aluminium and a little natural radiation.

Family
Quartz
Formula
SiO₂
Mohs
7
System
Trigonal

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Science

Smoky quartz gets its colour when aluminium substituting for silicon is exposed to natural radiation from surrounding granite. The shade runs from pale tan to nearly black morion. Because the process is so simple, much of the very dark smoky quartz on the market has been irradiated artificially.

Mineral
Quartz (variety)
Formula
SiO₂
Crystal system
Trigonal
Mohs hardness
7
Specific gravity
2.65
Refractive index
1.544 to 1.553
Lustre
Vitreous
Colours
Brown, Grey, Black

Composition

SiO₂. Made of Silicon, Oxygen, with trace Aluminium responsible for colour.

in formula trace, gives colour

Origin

  • Brazil
  • Scotland
    Cairngorm Mountains
  • Switzerland
    Alpine clefts
  • United States
    Colorado, New Hampshire
  • Madagascar
  • Australia

Filled dots are primary sources

Rarity

Abundant
1 of 5

Common worldwide. Gem-clear Alpine crystals with sharp terminations are the collectable grade.

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

Hardness

Smoky Quartz sits at 7 on the Mohs scale. It will scratch glass and holds a polish in daily wear.

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

  • Root

Element

  • Earth

Zodiac

  • Capricorn
  • Scorpio
  • Sagittarius

Planets

  • Saturn

Properties

  • Grounding
  • Release
  • Protection
  • Stress relief
  • Practicality

Lore

It is the national gem of Scotland. Highlanders set cairngorm in brooches and the pommels of dirks, and it remains the traditional stone of the kilt pin.

In the 12th century Chinese artisans made the first sunglasses from flat panes of smoky quartz, worn by judges to hide their expressions in court.

  • State gem
    New Hampshire adopted smoky quartz in 1985.
  • Morion
    The nearly opaque black variety, common in irradiated granite pegmatites.