Mineralogy Database

Poldervaartite Mineral Data

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General Poldervaartite Information

Help on Chemical  Formula: Chemical Formula: (Ca,Mn++)2SiO3(OH)2
Help on Composition: Composition: Molecular Weight = 197.68 gm
   Calcium    30.41 %  Ca   42.55 % CaO
   Manganese  13.90 %  Mn   17.94 % MnO
   Silicon    14.21 %  Si   30.39 % SiO2
   Hydrogen    1.02 %  H     9.11 % H2O
   Oxygen     40.47 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca1.5Mn2+0.5SiO3(OH)2
Help on Environment: Environment: In a pocket in massive manganese ores in a bedded manganese ore deposit.
Help on IMA Status: IMA Status: Approved IMA 1993
Help on Locality: Locality: Wessels mine, near Kuruman, Cape Province, South Africa. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Arie Poldervaart (1918-1964), Professor of Petrology, Columbia University, New York City, New York, USA.
Help on Name Pronunciation: Name Pronunciation: Poldervaartite + Pronunciation Say POLDERVAARTITE
Help on Synonym: Synonym: ICSD 74005
  PDF 46-1435

Poldervaartite Image

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Comments: Moderate reddish tint to yellowish poldervaartite crystalline druze on matrix.
Location: N'chwaning II mine, section 5 south, stope 46-47 roof, Kuruman, Kalahari desert, South Africa. Scale: 6 x 3.5 x 4 cm.
© Fabre Minerals

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  Bultfonteinite   Poldervaartite

Comments: Bow-tie clusters of white, acicular bultfonteinite and blocky, beige-colored poldervaartite on matrix.
Location: N'Chwaning mine, South Africa. Scale: picture size 4 cm.
© John Veevaert

Poldervaartite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.0283:1:1.1527
Help on Cell Dimensions: Cell Dimensions: a = 9.398, b = 9.139, c = 10.535, Z = 8; V = 904.83 Den(Calc)= 2.90
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P bca
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.231(1), 4.18(0.45), 2.846(0.42),

Physical Properties of Poldervaartite

Help on Cleavage: Cleavage: None
Help on Color: Color: Colorless, Milky white.
Help on Density: Density: 2.91
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Hardness: Hardness: 5 - Apatite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Poldervaartite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.013 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2218,KPDmeas= 0.2211,KC= 0.2189
Ncalc = 1.63 - 1.64
Help on Optical Data: Optical Data: Biaxial (+), a=1.634, b=1.64, g=1.656, bire=0.0220, 2V(Calc)=64, 2V(Meas)=63-65.

Calculated Properties of Poldervaartite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.90 gm/cc
note: Specific Gravity of Poldervaartite =2.91 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0072410959
Boson Index = 0.9927589041
Help on Photoelectric: Photoelectric: PEPoldervaartite = 7.75 barns/electron
U=PEPoldervaartite x rElectron Density= 22.48 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Poldervaartite is Not Radioactive

Poldervaartite Classification

Help on  Dana Class: Dana Class: (78)Unclassified silicates
  (78.01)possible nesosilicates
  (78.01.08)Dana Group Poldervaartite (Ca,Mn)2SiO3(OH)2 P bca 2/m 2/m 2/m Olmiite! CaMn[SiO3(OH)](OH) P bca 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.AF.90 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AF -Nesosilicates with additional anions;
09.AF.90 Poldervaartite (Ca,Mn)2SiO3(OH)2 P bca 2/m 2/m 2/m
09.AF.90 Olmiite! CaMn[SiO3(OH)](OH) P bca 2/m 2/m 2/m

Other Poldervaartite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Am.Min.,Vol.78,p1082-1087,1993) OPTIC PROP.(Am.Min.,Vol.78,p1082-1087,1993)
Help on See Also: See Also: Links to other databases for Poldervaartite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 09.AF.90





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