Petalite

Petalite is named after Greek "petalon" - leaf, because of its perfect cleavage.

Well-formed crystals are rare, it is usually found in its massive form. Stones with colour are sometimes cut into cabochons. Cut petalite stones exhibit a glassy appearance and can be confused with Glass.

Petalite cat's eye is known.

Petalite Gemstones by Colour

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

Petalite Gemstones by Size

This table shows distribution of Petalite 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:0.33 cts
Heaviest:12.40 cts
Average:3.94 cts
Total photos:19
Do you have a larger Petalite? Why not upload a photo?
0.33ct to 1.54ct1.54ct to 2.74ct2.74ct to 3.95ct3.95ct to 5.16ct5.16ct to 6.37ct6.37ct to 7.57ct7.57ct to 8.78ct8.78ct to 9.99ct9.99ct to 11.19ct11.19ct to 12.40ct
General Information
Chemical Formula
LiAlSi
 
4
O
 
10
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Petalite
Mohs Hardness6 to 6.5
Walter Schumann, Gemstones of the world (2001)
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Specific Gravity2.40
Walter Schumann, Gemstones of the world (2001)
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TenacityBrittle
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Cleavage QualityPerfect
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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FractureConchoidal
Walter Schumann, Gemstones of the world (2001)
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Optical Properties of Petalite
Refractive Index1.502 to 1.523
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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Birefringence0.012 to 0.016
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
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Dispersion0.0141
Arthur Thomas, Gemstones (2009)
Colour
Colour (General)Colourless, pink, yellowish
Walter Schumann, Gemstones of the world (2001)
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TransparencyTransparent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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LustrePearly
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Fluorescence & other light emissions
Fluorescence (General)May react white to weak orange
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Crystallography of Petalite
Crystal SystemMonoclinic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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HabitThick tabular, columnar and aggregates
Walter Schumann, Gemstones of the world (2001)
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Geological Environment
Where found:Petalite is a mineral of granite pegmatites where it may be found with other Li-minerals including spodumene and tourmaline group species.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Petalite information at mindat.org
Significant Gem Localities
Australia
 
  • Western Australia
    • Coolgardie Shire
      • Nepean
Brazil
 
  • Minas Gerais
Gemstones of the World, W.Schumann, 2001, p.188
Italy
 
  • Tuscany
    • Livorno Province
      • Elba Island
        • Campo nell'Elba
Gemstones of the World, W.Schumann, 2001, p.188
          • Sant'Ilario in Campo
Gemstones of the World, W.Schumann, 2001, p.188
Sweden
 
  • Västerbotten County
    • Skellefteå
      • Skellefte mining district
Gemstones of the World, W.Schumann, 2001, p.188
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.