Zircon

Big Photo

Tanzania
47.19 carats
© gemselect.com

Zircon has been known since antiquity, albeit under various names. Today's name is most likely derived from the Persian language ("golden colored"). Because of its high refractive index and strong dispersion, it has great brilliance and intensive fire.

Zircons with the highest values in optical properties are designated as high zirons, those with the lowest values as low zircons. In between are the medium zircons.

Zircon Gemstones by Colour

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

Zircon Gemstones by Size

This table shows distribution of Zircon 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:0.25 cts
Heaviest:47.35 cts
Average:5.78 cts
Total photos:116
Do you have a larger Zircon? Why not upload a photo?
0.25ct to 4.96ct4.96ct to 9.67ct9.67ct to 14.38ct14.38ct to 19.09ct19.09ct to 23.80ct23.80ct to 28.51ct28.51ct to 33.22ct33.22ct to 37.93ct37.93ct to 42.64ct42.64ct to 47.35ct
General Information
Varieties/Types:
Hyacinth - Yellow-red to red-brown zircon.
Starlite - Blue heat-treated zircon.
Chemical Formula
ZrSiO
 
4
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Photos of natural/un-cut material from mindat.org
Zircon Treatments
The brown varieties are heat-treated at temperatures of 1472-1832 degrees F (800-1000 degrees C), producing colorless and blue zircons. These colors do not necessarily remain constant; ultraviolet rays or sunlight can produce changes. - Gemstones of the world, Walter Schumann, 2001, p 108
Synthetic Zircon
Synthetic zircons are only of scientific interest. - Gemstones of the world, Walter Schumann, 2001, p 108
Physical Properties of Zircon
Mohs Hardness7.5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) High typeMore from other references
Specific Gravity3.93 to 4.73
Walter Schumann, Gemstones of the world (2001)
More from other references
TenacityBrittle
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) May show abraded facet junctions, brittleness increasing with heat-treatmentMore from other references
Cleavage QualityIndistinct
Walter Schumann, Gemstones of the world (2001)
More from other references
FractureConchoidal
Arthur Thomas, Gemstones (2009)
Optical Properties of Zircon
Refractive Index1.810 to 2.024
Walter Schumann, Gemstones of the world (2001)
More from other references
Optical CharacterUniaxial/+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Birefringence0.045 to 0.059
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) High typeMore from other references
PleochroismRed zircon - distinct: purplish-red - reddish-brown; Orange/brown zircon - weak: yellow-brown - red-brown; Yellow - weak: honey-yellow - brown-yellow; Blue - strong: colorless to gray - blue; Green - weak: brownish-green - green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Dispersion0.039
Michael O’Donoghue, Gems, Sixth Edition (2006) In the heat-treated colourless material when facetedMore from other references
ChatoyancyLow type: star 4
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Colour
Colour (General)Colourless, blue, green, yellow-green, yellow, green-brown, brown, yellow-red, red
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
Colour (Chelsea Filter)Blue color: greenish; green color: may appear pinkish
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Causes of ColourBlue, U4+. Red, Nb4+ color centers.
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent,Translucent
Arthur Thomas, Gemstones (2009)
LustreVitreous
Walter Schumann, Gemstones of the world (2001) Vitreous luster to a brilliant sheen.More from other references
Fluorescence & other light emissions
Fluorescence (General)Blue: very weak - light orange. Red and brown: weak - dark yellow
Walter Schumann, Gemstones of the world (2001)
Fluorescence (Short Wave UV)Inert to orangy-yellow
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Zircon
Crystal SystemTetragonal
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
HabitShort, stocky 4-sided prisms with pyramidal ends
Walter Schumann, Gemstones of the world (2001)
More from other references
Geological Environment
Where found:Most gem zircon occurs as pebbles in gem gravels.
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Spectrographic Data
Calculated Spectra:
Click spectra for more information
Zircon - Locality: Unknown (possibly Burma)
Zircon - Locality: Unknown (possibly Cambodia)
Zircon - Locality: Tanzania
Inclusions in Zircon
Repeated twining and zoning, angular "skeletal-like" tension fissures, needle-like inclusions are common for low type zircon.
Needle-like inclusions, lamellar structure, liquid inclusions, healing cracks - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 28
Further Information
Mineral information:Zircon information at mindat.org
Significant Gem Localities
Australia
 
  • Northern Territory
    • Central Desert Region
      • Alcoota Station
Faulkner and Shigley (1989)
  • Queensland
    • Central Highlands Region
F.L. Sutherland (1999)
Cambodia
 
  • Krong Pailin Municipality (Pailin Municipality)
mindat.org
  • Rattanakiri Province (Ratanakiri Province; Rotanokiri Province)
mindat.org
China
 
  • Fujian Province
    • Sanming Prefecture
    • Ding'an Co.
      • Penglai
  • Jiangsu Province
    • Nanjing Prefecture
Kyrgyzstan
 
  • Naryn Oblast
Madagascar
 
  • Fianarantsoa Province
    • Horombe Region
      • Ihosy District
        • Ilakaka Commune
Hanni (1999)
  • Tuléar Province (Toliara)
    • Anosy Region (Fort Dauphin Region)
Hanni (1999)
Myanmar
 
  • Mandalay Region (Mandalay Division)
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Bernardmyo
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Kyatpyin Central
          • Baw-lon-gyi (Big Ball)
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Kyauk-Pyat-That
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
          • Yadanar-kaday-kadar
Ted Themelis (2008) Gems & mines of Mogok
        • Marble Ark
Ted Themelis (2008) Gems & mines of Mogok
        • Mogok Valley
          • Dattaw-taung (Dattaw hill)
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Pein-Pyit (Painpyit; Pyan Pyit)
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
  • Sagaing Region (Sagaing Division)
    • Katha District
      • Wuntho Township
Ted Themelis (2008) Gems & mines of Mogok
Russia
 
  • Far-Eastern Region
    • Primorskiy Kray
      • Roshchino
        • Kedrovaya river
  • Urals Region
    • Southern Urals
      • Chelyabinsk Oblast'
Y. Shelementiev (1999)
Y. Shelementiev (1999)
Sri Lanka
 
  • Central Province
Milisenda and Henn (1999)
  • Sabaragamuwa Province
    • Ratnapura District
Milisenda and Henn (1999)
      • Embilipitiya (Embilipitya; Ambilipitiya)
Milisenda and Henn (1999)
Milisenda and Henn (1999)
Econ Geol (1981) 76:733-738
Tanzania
 
  • Ruvuma Region
    • Tunduru District
gemexplorer.org
Thailand
 
E.Ya. Kievlenko (2003) Geology of gems, p. 44
    • Bo Rai District
Vietnam
 
  • Đồng Nai Province
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