Amethyst

Big Photo

Amethyst Super Trillion Cut
105.01 carats
© johndyergems.com

Amethyst is the name given to purple to mauve quartz.

The name comes from the Ancient Greek ("not intoxicated"), a reference to the belief that the stone protected its owner from drunkenness. The ancient Greeks and Romans wore amethyst and made drinking vessels of it in the belief that it would prevent intoxication.

The range of colour includes reddish-violet tints of pale or almost colourless shades, and deep, rich tones of pure violet.

Amethyst Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
 
 
 
 
 

Amethyst Gemstones by Size

This table shows distribution of Amethyst gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:0.34 cts
Heaviest:105.01 cts
Average:13.76 cts
Total photos:111
Do you have a larger Amethyst? Why not upload a photo?
0.34ct to 10.81ct10.81ct to 21.27ct21.27ct to 31.74ct31.74ct to 42.21ct42.21ct to 52.68ct52.68ct to 63.14ct63.14ct to 73.61ct73.61ct to 84.08ct84.08ct to 94.54ct94.54ct to 105.01ct
General Information
A variety or type of:Quartz
Chemical Formula
SiO
 
2
Walter Schumann, Gemstones of the world (2001)
Photos of natural/un-cut material from mindat.org
Amethyst Treatments
Heat treatment between 878 - 1382 degrees F (470 - 750 degrees C) produces light yellow, red-brown, green, or colorless varieties. The original color an be restored by X-ray radiation. - Gemstones of the world, Walter Schumann, 2001, p 118
Physical Properties of Amethyst
Mohs Hardness7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.65
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
TenacityBrittle
Walter Schumann, Gemstones of the world (2001) Very brittle
Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
FractureConchoidal
Walter Schumann, Gemstones of the world (2001)
Heat SensitivityThe colour does not resist high temperatures. When subjected to the action of heat it changes first to a more or less pronounced yellow, gradually assumes a greenish shade, and finally disappears.
Max Bauer, Precious Stones (1968) Dover Publications
Optical Properties of Amethyst
Refractive Index1.544 to 1.553
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Birefringence0.009
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
PleochroismWeak: (gray)-purple - reddish-purple
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Dispersion0.013
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)Purple, violet, pale red-violet
Walter Schumann, Gemstones of the world (2001)
More from other references
Colour (Daylight)Some amethysts lose some color in daylight.
Walter Schumann, Gemstones of the world (2001)
Colour (Chelsea Filter)Reddish
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Causes of ColourViolet to purple, O2+Fe4+ charge transfer, due to irradiation.
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent,Translucent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Fluorescence & other light emissions
Fluorescence (General)Inert to weak greenish or bluish
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Amethyst
Crystal SystemTrigonal
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
HabitHexagonal prisms
Walter Schumann, Gemstones of the world (2001)
Geological Environment
Where found:Found in geodes in alluvial deposits.
Walter Schumann, Gemstones of the world (2001)
Inclusions in Amethyst
Typical "zebra stripe" pattern, 2 phase inclusions in veil-like pattern - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7
Healing cracks ("tiger-stripes"), Brazilian law twinning - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 9
Further Information
Mineral information:Amethyst information at mindat.org
Significant Gem Localities
Afghanistan
 
  • Ghazni Province (Gazni Province)
    • Qarabagh District
      • Zarkashan Mt (Zarkishen; Zerkishen)
Laurs (2002)
Bolivia
 
  • Santa Cruz Department
    • Sandoval Province
      • La Gaiba District
Laurs (2001, 2010)
Laurs (2001, 2010)
Laurs (2001, 2010)
Brazil
 
  • Bahia
    • Lagoa Real U province
      • Caetité
Couto (2000)
  • Rio Grande do Sul
    • Alto Uruguai region
Priester (1999)
Balzer (1999)
Rocks & Min.:5:131.
Rocks & Min.: 5:131.
    • Passo Fundo
Rocks & Min.:5:131.
  • Rondônia
    • Porto Velho
R. Batista and D. Epstein (2000)
Cambodia
 
Ngu and Ngoc (1986)
Canada
 
  • Ontario
Garland (2004)
      • McTavish Township
Sinkankas (1997)
Sinkankas (1997)
India
 
S. Fernandes (1999)
Kenya
 
  • Eastern Province
    • Kitui District
Henn and Milisenda (2001)
Madagascar
 
  • Antananarivo Province
    • Analamanga Region
      • Ankazobe Pegmatite Field
Madagascar, extraLapis English No.1, 2001, p. 44
  • Antsiranana Province
    • Diana Region (Northern Region)
Pezzotta (1999)
  • Fianarantsoa Province
    • Horombe Region
      • Ranohira District
        • Ilakaka Commune
Madagascar - extraLapis English No.1, p. 92
  • Toamasina Province (Tamatave)
    • Alaotra-Mangoro Region
      • Andilamena District
Aurisicchio et al. (1999)
Mexico
 
  • Guerrero
    • Mun. de Zumpango del Rio
Ontiveros et al. (2004)
Ontiveros et al. (2004)
Myanmar
 
  • Mandalay Division
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Kyauk-Pyat-That
Ted Themelis (2008) Gems & mines of Mogok
        • Mogok Valley
Ted Themelis (2008) Gems & mines of Mogok
  • Sagaing Division
    • Katha District
      • Wuntho Township
Ted Themelis (2008) Gems & mines of Mogok
Namibia
 
  • Erongo Region
    • Brandberg Area
Michelou (2006)
Nigeria
 
  • Taraba State
Laurs and Koivula (2003)
Peru
 
  • Ancash Department
Russia
 
  • Eastern-Siberian Region
    • Sakha Republic (Saha Republic; Yakutia)
V. Bukanov (1999)
  • Far-Eastern Region
    • Magadanskaya Oblast'
P. Lyckberg (2009)
  • Northern Region
    • Murmanskaja Oblast'
      • Kola Peninsula
        • Tersky Bereg
V. Bukanov (1999)
  • Urals Region
    • Southern Urals
      • Chelyabinsk Oblast'
South Korea
 
  • Gyeongsangnam-do (Kyongsang-namdo)
Yang et al. (2001)
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
Uruguay
 
  • Artigas Department
Gilg et al. (2003)
mindat.org
USA
 
  • Arizona
    • Maricopa Co.
      • Mazatzal Mts
        • Four Peaks
Lowell and Koivula (2004)
  • Georgia
    • Wilkes Co.
      • Jacksons Crossroads
Laurs (2005)
Copyright © Jolyon & Katya Ralph 1993-2016. Site Map. Locality, gem & photograph data are the copyright of the individuals who submitted them. For more information please contact the . Gemdat.org is an online information resource dedicated to providing free gemmological information to all.