Vivianite

Vivianite is named after John Henry Vivian, who first discovered crystals of the mineral at St Agnes, Cornwall, England.

Vivianite forms flattened prismatic transparent to translucent light green to deep blue or colourless crystals. It has very strong plechroism: deep blue - pale yellowish green - yellowish green.

Facetable crystals are rare.
General Information
Chemical Formula
Fe
 
3
(PO
 
4
)
 
2
8H
 
2
O
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Photos of natural/un-cut material from mindat.org
Physical Properties of Vivianite
Mohs Hardness1.5 to 2
Walter Schumann, Gemstones of the world (2001)
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Specific Gravity2.64 to 2.70
Walter Schumann, Gemstones of the world (2001)
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TenacityFlexible
Anthony et al, Handbook of mineralogy (2001)
Cleavage QualityPerfect
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Light SensitivityAlters to blue or green on exposure to light
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Optical Properties of Vivianite
Refractive Index1.560 to 1.640
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Optical CharacterBiaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Birefringence0.054 to 0.075
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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PleochroismAnomalous plechroism is strong with colours deep blue/pale yellowish green/yellowish green.
Michael O’Donoghue, Gems, Sixth Edition (2006)
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DispersionWeak
Anthony et al, Handbook of mineralogy (2001)
Colour
Colour (General)Blue-green, deep blue, colourless
Walter Schumann, Gemstones of the world (2001)
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TransparencyTransparent,Translucent
Walter Schumann, Gemstones of the world (2001)
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LustreVitreous,Pearly,Dull (Earthy)
Anthony et al, Handbook of mineralogy (2001) Pearly on the cleavage, dull when earthy.
Crystallography of Vivianite
Crystal SystemMonoclinic
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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HabitPrismatic
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Geological Environment
Where found:Vivianite occurs as a secondary mineral in the oxidized zone of metallic-ore deposits and in complex granite pegmatites.
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Further Information
Mineral information:Vivianite information at mindat.org
Significant Gem Localities
Bolivia
 
  • Oruro
    • Poopó Province
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 464
  • Potosí
    • Nor Chichas Province
      • Atocha-Quechisla District
    • Rafael Bustillo
      • Llallagua
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 464
Cameroon
 
  • Adamaoua Region
    • Adamaoua Plateau (Adamawa Plateau)
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 464
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