Demantoid

Big Photo

Russia
2.09 carats
© Palagems

Demantoid is the green gemstone variety of andradite, a member of the garnet group of minerals. It is the most valuable garnet (name means "diamond-like luster).

The demantoid was discovered in 1868 in Russia's western central Ural Mountains.

Demantoid Gemstones by Colour

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

Demantoid Gemstones by Size

This table shows distribution of Demantoid 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:0.48 cts
Heaviest:4.24 cts
Average:1.40 cts
Total photos:23
Do you have a larger Demantoid? Why not upload a photo?
0.48ct to 0.86ct0.86ct to 1.23ct1.23ct to 1.61ct1.61ct to 1.98ct1.98ct to 2.36ct2.36ct to 2.74ct2.74ct to 3.11ct3.11ct to 3.49ct3.49ct to 3.86ct3.86ct to 4.24ct
General Information
A variety or type of:Andradite, which is a variety of Garnet Group
Chemical Formula
Ca
 
3
Fe
 
2
(SiO
 
4
)
 
3
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Photos of natural/un-cut material from mindat.org
Physical Properties of Demantoid
Mohs Hardness6.5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Specific Gravity3.77 to 3.95
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical Properties of Demantoid
Refractive Index1.880 to 1.890
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterIsotropic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Anomalous double refraction
Colour
Colour (General)Green, yellowish-green
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Colour (Chelsea Filter)Inert to reddish
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Causes of ColourGreen, Cr3+ in octahedral coordination.
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Fluorescence & other light emissions
Fluorescence (General)Inert
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Demantoid
Crystal SystemIsometric
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Inclusions in Demantoid
Radiating chrysotile fibres ("horse-tail") - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 29
Further Information
Mineral information:Demantoid information at mindat.org
Significant Gem Localities
Canada
 
  • Québec
    • Chaudière-Appalaches
      • Les Appalaches RCM
        • Saint-Joseph-de-Coleraine
Wilson (2007)
Wilson (2007)
Iran
 
  • Kerman
    • Baft County
Laurs (2002)
Italy
 
  • Lombardy
    • Sondrio Province
      • Valtellina
Zang (2008)
Madagascar
 
  • Diana
    • Ambanja
      • Antsakoamanondro
Danet (2009)
Mexico
 
  • Sonora
Namibia
 
  • Erongo Region
    • Dâures
      • Tubussis Farm 22 (Tubussis; Tubusis; Tubessis)
Laurs (2002)
Russia
 
  • Chelyabinsk Oblast
    • Verkhny Ufaley
      • Ufaley District (Ufalei District)
        • Korkodin
Korchevskaya (2006)
  • Sverdlovsk Oblast
    • Yekaterinburg
Zang (2008)
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
Copyright © Jolyon & Katya Ralph 1993-2019. 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.