Poldervaartite

Big Photo

South Africa
0.81 carats
© Mineral Classics

Poldervaartite is named after Arie Poldervaart, Professor of Petrology, Columbia University, New York, USA.

Poldervaartite forms colourless, milky white, light orange-pink, pink-white prismatic crystals.

The material suitable for faceting is scarce.

Poldervaartite Gemstones by Colour

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

Poldervaartite Gemstones by Size

This table shows distribution of Poldervaartite 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
Heaviest:0.81 cts
Average:0.81 cts
Total photos:2
Do you have a larger Poldervaartite? Why not upload a photo?

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0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct0.81ct to 0.81ct
General Information
Chemical Formula
(Ca,Mn
2+
 
)
 
2
(SiO
 
3
OH)(OH)
Anthony et al, Handbook of Mineralogy (2001)
Photos of natural/un-cut material from mindat.org
Physical Properties of Poldervaartite
Mohs Hardness5
Anthony et al, Handbook of Mineralogy (2001)
Specific Gravity2.91
Anthony et al, Handbook of Mineralogy (2001)
TenacityBrittle
Anthony et al, Handbook of Mineralogy (2001) Very brittle
Optical Properties of Poldervaartite
Refractive Index1.634 to 1.656
Anthony et al, Handbook of Mineralogy (2001)
Optical CharacterBiaxial/+
Anthony et al, Handbook of Mineralogy (2001)
PleochroismWeak: colorless - light gray - bluish gray
Anthony et al, Handbook of Mineralogy (2001)
DispersionWeak
Anthony et al, Handbook of Mineralogy (2001)
Colour
Colour (General)Colorless to white
Anthony et al, Handbook of Mineralogy (2001)
TransparencyTransparent,Translucent
Anthony et al, Handbook of Mineralogy (2001)
LustreVitreous
Anthony et al, Handbook of Mineralogy (2001) Vitreous on fractures to subvitreous on crystal faces
Fluorescence & other light emissions
Fluorescence (Short Wave UV)Fluoresces deep red under SW
Anthony et al, Handbook of Mineralogy (2001)
Crystallography of Poldervaartite
Crystal SystemOrthorhombic
Anthony et al, Handbook of Mineralogy (2001)
HabitCrystals are prismatic, to 7 mm; aggregates in sheaves.
Anthony et al, Handbook of Mineralogy (2001)
Geological Environment
Where found:In a pocket in massive manganese ores in a bedded manganese ore deposit.
Anthony et al, Handbook of Mineralogy (2001)
Further Information
Mineral information:Poldervaartite information at mindat.org
Significant Gem Localities
South Africa
 
  • Northern Cape
    • Kalahari manganese field
      • Kuruman
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