Danburite

Big Photo

Danburite Dreamscape Cut
24.33 carats
© johndyergems.com

Danburite was first found in Danbury (therefore the name), Connecticut, USA.

Danburite is little known as a gemstone, but its popularity is growing. Its crystals have excellent clarity and they are easy to cut into brilliant attractive gems. Cut stones of 3-6 carats or more (up to 100 carats).

Danburite Gemstones by Colour

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

Danburite Gemstones by Size

This table shows distribution of Danburite 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:0.95 cts
Heaviest:41.44 cts
Average:10.07 cts
Total photos:35
Do you have a larger Danburite? Why not upload a photo?
0.95ct to 5.00ct5.00ct to 9.05ct9.05ct to 13.10ct13.10ct to 17.15ct17.15ct to 21.20ct21.20ct to 25.24ct25.24ct to 29.29ct29.29ct to 33.34ct33.34ct to 37.39ct37.39ct to 41.44ct
General Information
Chemical Formula
CaB
 
2
(SiO
 
4
)
 
2
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Photos of natural/un-cut material from mindat.org
Danburite Treatments
A pink color has been noted to form on irradiation (C.L. Key, unpublished observation). One would expect this to bleach on being heated; fading in light is also a possibility - Nassau (1984)
Physical Properties of Danburite
Mohs Hardness7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Specific Gravity2.97 to 3.03
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Cleavage QualityImperfect
Walter Schumann, Gemstones of the world (2001)
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FractureUneven,Conchoidal
Walter Schumann, Gemstones of the world (2001)
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Optical Properties of Danburite
Refractive Index1.627 to 1.639
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Optical CharacterBiaxial/+,-
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Birefringence0.006
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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PleochroismWeak: pale yellow - yellow
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Dispersion0.017
Arthur Thomas, Gemstones (2009)
Colour
Colour (General)Yellow, yellow-brown, brown, pink, colourless
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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TransparencyTransparent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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LustreVitreous
Arthur Thomas, Gemstones (2009)
Fluorescence & other light emissions
Fluorescence (Short Wave UV)Weaker than LW
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Fluorescence (Long-Wave UV)Inert to bright blue or blue-green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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ThermoluminescenceRed
Michael O’Donoghue, Gems, Sixth Edition (2006)
Crystallography of Danburite
Crystal SystemOrthorhombic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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HabitPrismatic with rhombohedral to square cross-section
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Geological Environment
Where found:Danburite occurs in granites and in metamorphosed carbonate rocks associated with hydrothermal activity
Michael O’Donoghue, Gems, Sixth Edition (2006)
Inclusions in Danburite
"Fingerprints", parallel growth tubes (may create chatoyancy) - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 4
Further Information
Mineral information:Danburite information at mindat.org
Significant Gem Localities
Burma (Myanmar)
 
  • Mandalay Division
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Mogok Valley
          • 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
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
    • Yamethin District
Ted Themelis (2008) Gems & mines of Mogok
  • Sagaing Division
    • Katha District
      • Wuntho
Ted Themelis (2008) Gems & mines of Mogok
Japan
 
  • Kyushu Region
    • Miyazaki Prefecture
      • Takachiho
Gemstones, Arthur Thomas, 2009, p.116
    • Oita Prefecture
      • Ono-gun
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 403
Madagascar
 
  • Antananarivo Province
    • Vakinankaratra Region
      • Betafo District
        • Ambohimanambola Commune
Mexico
 
  • Baja California (Baja California Norte; BC Norte)
    • Mun. de Ensenada
      • La Huerta
  • San Luis Potosí
    • Mun. de Charcas
Gemstones, Arthur Thomas, 2009, p.116
USA
 
  • Connecticut
    • Fairfield Co.
Copyright © Jolyon & Katya Ralph 1993-2014. 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.