Legrandite

Big Photo

Mexico
0.45 carats
© Rarestone.com

Legrandite is named after Mr. Legrand, Belgian mining engineer, collector of the first specimen from Flor de Pina mine, Nueva Leon, Mexico.

Legrandite forms in tight clusters and sometimes transparent bright yellow, orange, colourless elongated prismatic crystals. These crystals are large enough to be faceted.

Legrandite Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
General Information
Chemical Formula
Zn
 
2
(AsO
 
4
)(OH) · H
 
2
O
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Photos of natural/un-cut material from mindat.org
Physical Properties of Legrandite
Mohs Hardness4.5 to 5
Walter Schumann, Gemstones of the world (2001)
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Specific Gravity3.98 to 4.04
Walter Schumann, Gemstones of the world (2001)
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TenacityBrittle
Anthony et al, Handbook of mineralogy (2001)
Cleavage QualityPoor
Arthur Thomas, Gemstones (2009)
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FractureUneven
Arthur Thomas, Gemstones (2009)
Optical Properties of Legrandite
Refractive Index1.702 to 1.740
Michael O’Donoghue, Gems, Sixth Edition (2006) RI for the alpha, beta and gamma rays is 1.702, 1.709, 1.740More from other references
Optical CharacterBiaxial/+
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Birefringence0.060
Michael O’Donoghue, Gems, Sixth Edition (2006)
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PleochroismYellow to colourless
Michael O’Donoghue, Gems, Sixth Edition (2006)
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DispersionStrong
Arthur Thomas, Gemstones (2009)
Colour
Colour (General)Yellow, colourless
Walter Schumann, Gemstones of the world (2001)
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TransparencyTransparent
Michael O’Donoghue, Gems, Sixth Edition (2006)
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LustreVitreous
Walter Schumann, Gemstones of the world (2001)
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Crystallography of Legrandite
Crystal SystemMonoclinic
Walter Schumann, Gemstones of the world (2001)
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HabitElongated prismatic crystals
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Geological Environment
Where found:An uncommon secondary mineral in the oxidized zone of Zn–As-bearing deposits; rare in granite pegmatite
Anthony et al, Handbook of mineralogy (2001)
Further Information
Mineral information:Legrandite information at mindat.org
Significant Gem Localities
Mexico
 
  • Durango
    • Mapimí Municipality
      • Mapimí
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 423
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