Adularia

Big Photo

Pakistan
0.87 carats
© raregemhunter

Adularia is transparent colourless form of Orthoclase with white to blue sheen. It can be faceted, but cut stones are usually unimpressive.

Adularia Gemstones by Colour

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

Adularia Gemstones by Size

This table shows distribution of Adularia 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:0.87 cts
Heaviest:3.09 cts
Average:1.98 cts
Total photos:2
Do you have a larger Adularia? Why not upload a photo?
0.87ct to 1.09ct1.09ct to 1.31ct1.31ct to 1.54ct1.54ct to 1.76ct1.76ct to 1.98ct1.98ct to 2.20ct2.20ct to 2.42ct2.42ct to 2.65ct2.65ct to 2.87ct2.87ct to 3.09ct
General Information
A variety or type of:Orthoclase, which is a variety of Feldspar
Chemical Formula
KAlSi
 
3
O
 
8
Michael O’Donoghue, Gems, Sixth Edition (2006)
Adularia Simulants
Adularescent synthetic spinel (possibly with mirror-like back coating), glass and with milky chalcedony. - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 8
Physical Properties of Adularia
Mohs Hardness6
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.54 to 2.61
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical Properties of Adularia
Refractive Index1.518 to 1.536
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterBiaxial/-
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Birefringence0.005 to 0.008
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Colour
Colour (General)Colourless
Arthur Thomas, Gemstones (2009)
TransparencyTransparent
Arthur Thomas, Gemstones (2009)
Fluorescence & other light emissions
Fluorescence (Short Wave UV)Inert to orangy-(reddish)
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Fluorescence (Long-Wave UV)Inert to blue (and pinkish)
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Adularia
Crystal SystemMonoclinic
Arthur Thomas, Gemstones (2009)
Geological Environment
Where found:Low temperature hydrothermal deposits (in the Swiss Alps).
Arthur Thomas, Gemstones (2009)
Inclusions in Adularia
Typical "centipede" inclusions. - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 8
Further Information
Mineral information:Adularia information at mindat.org
Significant Gem Localities
Austria
 
  • Salzburg
    • Hohe Tauern
      • Habach valley
        • Nasenkopf
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
USA
 
  • California
    • El Dorado Co.
      • Fallen Leaf
Rogers, Austin Flint (1912), Notes on rare minerals from California: Columbia University, School of Mines Quarterly: 33: 376; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 184.
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