Lapidarium
← All stones

Amethyst

Purple quartz, once priced beside ruby, now the most familiar stone in the world.

Family
Quartz
Formula
SiO₂
Mohs
7
System
Trigonal

Science

Amethyst is quartz coloured by trace iron that has been irradiated inside the rock over geological time. Until Brazil's vast deposits were found in the 1800s it was ranked with the cardinal gems. Heating amethyst above roughly 400 °C turns it orange or yellow, which is where most commercial citrine comes from.

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
Purple, Violet, Lavender
Birthstone
February

Composition

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

in formula trace, gives colour

Origin

  • Brazil
    Rio Grande do Sul geodes
  • Uruguay
    Artigas, deep-colour material
  • Zambia
  • Russia
    Siberian, historic
  • South Africa
  • Madagascar

Filled dots are primary sources

Rarity

Abundant
1 of 5

Abundant since the 19th-century Brazilian finds. Deep, evenly saturated stones are the only scarce grade.

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

Hardness

Amethyst 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

  • Third Eye
  • Crown

Element

  • Air

Zodiac

  • Pisces
  • Aquarius
  • Virgo
  • Capricorn

Planets

  • Jupiter
  • Neptune

Properties

  • Calm
  • Clarity
  • Sleep
  • Sobriety
  • Intuition
  • Protection

Lore

The name is the Greek amethystos, 'not drunk'. Greeks and Romans drank from amethyst cups and wore it as a charm against intoxication, a belief Pliny recorded with some scepticism.

Medieval bishops wore amethyst rings as a sign of sober judgement, and the stone appears in the breastplate of the high priest in Exodus in most translations. In modern practice it is the default stone for calm and clear thinking.

  • Colour cause
    Fe³⁺ centres created by natural gamma radiation in the host rock.
  • Largest
    Uruguayan geodes several metres tall have been cut open and shipped whole.