Uvite Series

Big Photo

Zambia
0.65 carats
© Brian Kosnar - Mineral Classics

Uvite is named after a province in Sri Lanka. Uvite is the magnesium/iron-rich member of the group. Despite having so many coloring ions like iron and magnesium, some specimens of uvite can be colorless. The typical specimens of uvite on the mineral markets tend to be an interesting dark green to almost black in color.
General Information
A variety or type of:Tourmaline
Chemical Formula
Ca(Mg
 
3
)MgAl
 
5
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
Gemdat.org, Management Team (2012)
Photos of natural/un-cut material from mindat.org
Physical Properties of Uvite Series
Mohs Hardness7.5 to 0
Anthony et al, Handbook of mineralogy (2001)
Specific Gravity2.97 to 3.14
Anthony et al, Handbook of mineralogy (2001)
TenacityBrittle
Anthony et al, Handbook of mineralogy (2001)
FractureUneven,Conchoidal
Anthony et al, Handbook of mineralogy (2001)
Optical Properties of Uvite Series
Refractive Index1.614 to 1.666
Walter Schumann, Gemstones of the world (2001)
Optical CharacterUniaxial/-
Anthony et al, Handbook of mineralogy (2001)
Birefringence0.014 to 0.032
Walter Schumann, Gemstones of the world (2001)
PleochroismPale yellow - colorless
Anthony et al, Handbook of mineralogy (2001)
Dispersion0.017
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)Brown, light to dark green, red, black; may be zoned parallel to prism faces.
Anthony et al, Handbook of mineralogy (2001)
Causes of ColourGreen ("chrome tourmaline"), V3+ generally with minor amounts of Cr3+, both in octahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent,Translucent
Anthony et al, Handbook of mineralogy (2001)
LustreVitreous,Resinous
Anthony et al, Handbook of mineralogy (2001)
Fluorescence & other light emissions
Fluorescence (Short Wave UV)May fluoresce a weak mustard-yellow
Anthony et al, Handbook of mineralogy (2001)
Crystallography of Uvite Series
Crystal SystemHexagonal
Anthony et al, Handbook of mineralogy (2001)
HabitCrystals prismatic to equant, may be tabular, pyramidal, in radiating groups, to 15 cm. Cross sections are typically triangular with curved, convex sides.
Anthony et al, Handbook of mineralogy (2001)
Geological Environment
Where found:Typically in calcium-rich rocks subjected to contact metamorphism and metasomatic processes which added boron.
Anthony et al, Handbook of mineralogy (2001)
Further Information
Mineral information:Uvite Series information at mindat.org
Significant Gem Localities
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
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