Poldervaartite

Formula: CaMn[SiO₃(OH)](OH) (Calcium dominant)
Mineral class: silicates
Crystal system: orthorhombic
Mohs scale: 5
Density (g/cm³): 2.91
Refractive index: 1.634 - 1.656
Cleavage: -
Colors: colorless, milky white, cream, yellowish
Transparency: transparent - translucent
Luster: vitreous - subvitreous
Fluorescence: SW: red
Pleochroism: -
Largest single poldervaartite crystal: 7 mm ?
Deposit: Wessels Mine / Hotazel / Northern Cape Province / South Africa
Discovery: 1993
1st description: Y. Dai, G.E. Harlow, and A.R. McGhie, 1993
Name: in honor of the U.S. geologist Arie Poldervaart (1918 - 1964)
History:
• Poldervaartite was found in 1993 in a pocket of the Wessels Mine in Kuruman, South Africa, associated with the minerals Henritermierite, Calcite, Bultfonteinite and Hematite.
• More than 50 attractive poldervaartite crystals were found in 1995 in single deposit at the Wessels mine, from micromount until cabinet size.

Poldervaartite Mineral

Size: 3.9 x 2.4 x 2.3 cm

Origin: Wessels Mine / Hotazel / Northern Cape Province / South Africa

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Poldervaartite

Size: 1.35 x 1.06 cm
Weight: 5.65 ct
Origin: South Africa

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Poldervaartite

Weight: 0.86 ct

Origin: Pakistan ?

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Poldervaartite

Weight: 0.54 ct

Origin: South Africa

Photo by kind permission of © Darlene Cobler