Lapidarium
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Diamond

Pure carbon crystallised under the continents, the hardest natural substance.

Family
Diamond
Formula
C
Mohs
10
System
Cubic

Science

Diamonds crystallise 150 kilometres down in the mantle and are carried up in kimberlite eruptions. Most are over a billion years old. Nitrogen tints them yellow; boron, blue; plastic deformation of the lattice, pink. High refractive index and dispersion give the fire, but only the brilliant cut, worked out in 1919, releases it fully.

Mineral
Diamond
Formula
C
Crystal system
Cubic
Mohs hardness
10
Specific gravity
3.52
Refractive index
2.417
Lustre
Adamantine
Colours
Colourless, Yellow, Brown, Pink, Blue
Birthstone
April

Composition

C. Made of Carbon, with trace Nitrogen, Boron responsible for colour.

in formula trace, gives colour

Origin

  • Russia
    Yakutia
  • Botswana
    Jwaneng, Orapa
  • Canada
    Northwest Territories
  • Democratic Republic of the Congo
  • South Africa
    Kimberley, Cullinan
  • Australia
    Argyle, closed 2020
  • India
    Golconda, historic

Filled dots are primary sources

Rarity

Uncommon
3 of 5

Diamond is mined by the hundred million carats a year; its scarcity is in gem grade and in fancy colours. Natural blue and pink stones are truly rare.

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

Hardness

Diamond sits at 10 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

  • Crown

Element

  • Fire

Zodiac

  • Aries
  • Leo
  • Libra

Planets

  • Sun
  • Venus

Properties

  • Clarity
  • Strength
  • Purity
  • Amplification
  • Commitment

Lore

India supplied the world's diamonds from the 4th century BCE until Brazil in the 1720s; the name is from adamas, 'unconquerable'. The Cullinan, 3,106 carats, was found in 1905 and cut into the British crown jewels.

The engagement diamond is a 20th-century invention, built by De Beers advertising from 1938 and the line 'A Diamond is Forever' in 1947.

  • Age
    Typically 1 to 3.5 billion years.
  • Lab-grown
    Chemically identical stones are now grown in weeks and make up a large share of the market.