Turquoise

Big Photo

Arizona, USA
47.74 carats
© Brian Kosnar - Mineral Classics

Turquoise was one of the earliest gems to be used for personal adornment. It was used by Ancient Egypt rulers around 5500 BC. The name Turquoise dates to 16th century and derived from Old French word for "Turkish", because it entered Western Europe through Asia Minor.

Turquoise is opaque sky-blue, blue-green or apple-green stone with brown, dark gray, or black veins of other minerals or the host rock. It can also be intergrown with malachite and chrysocolla.

Turquoise Gemstones by Colour

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

Turquoise Gemstones by Size

This table shows distribution of Turquoise 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:2.04 cts
Heaviest:47.74 cts
Average:7.03 cts
Total photos:23
Do you have a larger Turquoise? Why not upload a photo?
2.04ct to 6.61ct6.61ct to 11.18ct11.18ct to 15.75ct15.75ct to 20.32ct20.32ct to 24.89ct24.89ct to 29.46ct29.46ct to 34.03ct34.03ct to 38.60ct38.60ct to 43.17ct43.17ct to 47.74ct
General Information
Chemical Formula
CuAl
 
6
(PO
 
4
)
 
4
(OH)
 
8
· 4H
 
2
O
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
Photos of natural/un-cut material from mindat.org
Turquoise Treatments
Commonly impregnated with wax to enchance color or plastic to increase durability: SG on low side, hot pont test, scratch test. May be dyed: color concentration along fractures. Acetone may reveal the dye if not coated. Zachery treatment tests limited. Porosity reduced: doesn't absorb liquids unlike most untreated natural stones, doesn't "discolor" in water. High quality polish. Even (strong) coloration, color concentration diffused along fractures - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5
Turquoise Simulants
Dyed howlite, dyed magnesite, variscite - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5
Synthetic Turquoise
Synthetic magnification: granular structure - "fish-eggs", "cream-of-wheat". May show black "spiderweb matrix" (rounded pattern). Strong transmitted light: usually translucent - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5
Physical Properties of Turquoise
Mohs Hardness5 to 6
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Specific Gravity2.30 to 2.90
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
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FractureConchoidal
Arthur Thomas, Gemstones (2009)
Optical Properties of Turquoise
Refractive Index1.610 to 1.650
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Optical CharacterBiaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Birefringence0.040
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
DispersionNone
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)Light blue, bluish-green, green, greenish-blue
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) Commonly with brownish or black veinsMore from other references
Colour (Chelsea Filter)No reaction
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Causes of ColourBlue, Cu2+ in octahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTranslucent,Opaque
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Strong transmitted light: appears opaque to semi-translucentMore from other references
LustreWaxy,Dull (Earthy)
Arthur Thomas, Gemstones (2009)
Fluorescence & other light emissions
Fluorescence (General)Weak; green-yellow, light blue
Walter Schumann, Gemstones of the world (2001)
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Fluorescence (Long-Wave UV)Inert to moderate whitish blue
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Turquoise
Crystal SystemTriclinic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
HabitFine-grained, massive aggregate, partly as nodules or botryoidal groups
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
Inclusions in Turquoise
May contain inclusions of pyrite, calcite, etc - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5
Further Information
Mineral information:Turquoise information at mindat.org
Significant Gem Localities
China
 
  • Hubei Province
    • Shiyan Prefecture
      • Yun Co.
Liu (1999)
Kenya
 
  • Coast Province
    • Taita Taveta District
Mexico
 
  • Sonora
    • Mun. de Cananea
Sinkankas (1997)
USA
 
  • Arizona
    • Cochise Co.
      • Dragoon Mts
        • Turquoise District (Courtland-Gleeson District)
          • Gleeson
Sinkankas (1997)
      • Mule Mts
        • Warren District
Sinkankas (1997)
    • Gila Co.
      • Globe-Miami District
        • Miami-Inspiration District
          • Miami
            • Sleeping Beauty Peak
              • Copper Cities Mine area
Sinkankas (1997)
    • Graham Co.
      • Gila Mts
        • Lone Star District (Safford District; Dos Pobres District)
          • Sanchez
Sinkankas (1997)
    • Greenlee Co.
      • Shannon Mts
        • Copper Mountain District (Clifton-Morenci District)
          • Morenci
Sinkankas (1997)
    • Mohave Co.
      • Cerbat Mts (Cerbat Range)
        • Wallapai District
          • Cerbat District
            • Cerbat
Sinkankas (1997)
  • California
    • San Bernardino Co.
      • Silver Lake District
        • Soda Mts
Sinkankas (1997)
  • Colorado
    • Saguache Co.
      • Bonanza District (Kerber Creek District)
Sinkankas (1997)
    • Teller Co.
Sinkankas (1997)
  • Nevada
    • Esmeralda Co.
Nevada, Lithographie, 2013, p. 53
    • Lander Co.
      • Bullion District
Nevada, Lithographie LTD, 2013
Sinkankas (1997)
      • Cortez District
Sinkankas (1997)
    • Nye Co.
      • San Antonio Mts
        • Tonopah District
          • Tonopah
Sinkankas (1997)
  • New Mexico
    • Grant Co.
      • Burro Mountains District
        • Tyrone Area
Sinkankas (1997)
Copyright © Jolyon & Katya Ralph 1993-2017. 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.