Beryllonite

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Stoneham, Oxford County, Maine, USA
20.65 carats
© Rarestone.com

Beryllonite is named because of its beryllium content. It was discovered by James Dwight Dana in 1888.

The crystals vary from colourless to white or pale yellowish, and are transparent with a vitreous lustre, and pearly luster on fracture planes. Beryllonite crystals are frequently heavily included. Beryllonite cat's eye is known.
9 photos

Beryllonite Gemstones by Colour

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

Beryllonite Gemstones by Size

This table shows distribution of Beryllonite 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:0.18 cts
Heaviest:20.65 cts
Average:6.11 cts
Total photos:9
Do you have a larger Beryllonite? Why not upload a photo?
0.18ct to 2.23ct2.23ct to 4.27ct4.27ct to 6.32ct6.32ct to 8.37ct8.37ct to 10.42ct10.42ct to 12.46ct12.46ct to 14.51ct14.51ct to 16.56ct16.56ct to 18.60ct18.60ct to 20.65ct
General Information
Chemical Formula
NaBePO
 
4
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Beryllonite
Mohs Hardness5.5 to 6
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Specific Gravity2.79 to 2.87
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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TenacityBrittle
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Cleavage QualityPerfect
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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FractureConchoidal
Arthur Thomas, Gemstones (2009)
Optical Properties of Beryllonite
Refractive Index1.552 to 1.562
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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Birefringence0.009 to 0.010
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
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Dispersion0.010
Michael O’Donoghue, Gems, Sixth Edition (2006) LowMore from other references
ChatoyancyYes
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Colour
Colour (General)Colourless, yellowish
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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LustrePearly,Dull (Earthy)
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Pearly luster may be seen on cleavage planeMore from other references
Fluorescence & other light emissions
Fluorescence (General)None
Walter Schumann, Gemstones of the world (2001)
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Fluorescence (X-RAY)A dark sky-blue fluorescence with slight phosphorescence
Michael O’Donoghue, Gems, Sixth Edition (2006)
Crystallography of Beryllonite
Crystal SystemMonoclinic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
HabitShort prisms
Arthur Thomas, Gemstones (2009)
Geological Environment
Where found:A mineral of granite and alkalic pegmatites
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Beryllonite information at mindat.org
Significant Gem Localities
USA
 
  • Maine
    • Oxford County
      • Stoneham
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 390
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