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Poldervaartite

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Big Photo

Wessels Mine (Wessel's Mine), Hotazel, Kalahari manganese fields, Northern Cape Province, South Africa
© 2005 M. Kampf

Show Poldervaartite Photos (3)



Formula:
CaCa[SiO
 
3
(OH)](OH)
System:OrthorhombicColour:colourless, milky white, ...
Hardness:5
Name:For Arie Poldervaart (1918-1964), petrologist, Columbia University, New York.


The Ca-dominant analogue of Olmiite.

Most (all?) "poldervaartites" seem to be olmiites, see http://www.mindat.org/mesg-7-104499.html.

Visit gemdat.org for gemological information about Poldervaartite. Currently in public beta-test.

Classification of Poldervaartite

IMA status:Approved 1992
Strunz 8th edition ID:8/B.22-25
Nickel-Strunz 10th (pending) edition ID:9.AF.90

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
Dana 8th edition ID:78.1.8.1

78 : Unclassified Silicates
1 : Miscellaneous
mindat.org URL:http://www.mindat.org/min-3252.html
Please feel free to link to this page.

Type Occurrence of Poldervaartite

Type Locality:Wessels Mine (Wessel's Mine), Hotazel, Kalahari manganese fields, Northern Cape Province, South Africa
Place of Conservation of Type Material:American Museum Natural History, New York T100728

Occurrences of Poldervaartite

Geological Setting:In massive manganese ore.

Physical Properties of Poldervaartite

Lustre:Vitreous, Sub-Vitreous
Diaphaneity (Transparency):Transparent, Translucent
Comment:Vitreous on fractures
Colour:colourless, milky white, pink-white
Streak:white
Hardness (Mohs):5
Tenacity:Very brittle
Cleavage:None Observed
Density (measured):2.91(2) g/cm3
Density (calculated):2.9 g/cm3

Crystallography of Poldervaartite

Crystal System:Orthorhombic
Class (H-M):mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:Pbca {P21/b 21/c 21/a}
Cell Parameters:a = 9.398(1) Å, b = 9.139(2) Å, c = 10.535(2) Å
Ratio:a:b:c = 1.028 : 1 : 1.153
Unit Cell Volume:V 904.83 ų (Calculated from Unit Cell)
Z:8
Morphology:Prismatic, sheaves
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Poldervaartite

Type:Biaxial (+)
RI values: nα = 1.634 nβ = 1.640 nγ = 1.656
2V:Measured: 63° to 65°, Calculated: 64°
Maximum Birefringence:δ = 0.022

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:r < v weak
Pleochroism:Weak
Comments:X= colorless
Y= light gray
Z= bluish gray

Chemical Properties of Poldervaartite

Formula:
CaCa[SiO
 
3
(OH)](OH)
Essential elements:Ca, H, O, Si
All elements listed in formula:Ca, H, O, Si
Common Impurities:Fe,Mg,H2O

Relationship of Poldervaartite to other Species

Series:Forms a series with Olmiite (see here)
Related Minerals - Nickel-Strunz Grouping):

- +
9.AF.05Sillimanite
Al
 
2
(SiO
 
4
)O
9.AF.10Andalusite
Al
 
2
(SiO
 
4
)O
9.AF.10Kanonaite
Mn
3+
 
Al(SiO
 
4
)O
9.AF.15Kyanite
Al
 
2
(SiO
 
4
)O
9.AF.20Mullite
Al
 
4+2x
Si
 
2-2x
O
 
10-x
9.AF.20Krieselite
(Al,Ga)
 
2
(GeO
 
4
)(OH)
 
2
9.AF.23Boromullite
Al
 
9
BSi
 
2
O
 
19
9.AF.25Yoderite
Mg(Al,Fe
3+
 
)
 
3
(SiO
 
4
)
 
2
O(OH)
9.AF.30Magnesiostaurolite
(Mg,Li,Fe
2+
 
)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH)
 
2
9.AF.30Staurolite
(Fe
2+
 
,Mg,Zn)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH,O)
 
2
9.AF.30Zincostaurolite
(Zn,Li,Fe
2+
 
,Mg)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH)
 
2
9.AF.35Topaz
Al
 
2
(SiO
 
4
)(F,OH)
 
2
9.AF.40Norbergite
Mg
 
3
(SiO
 
4
)(F,OH)
 
2
9.AF.45Alleghanyite
Mn
2+
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.45Chondrodite
(Mg,Fe
2+
 
)
 
5
(SiO
 
4
)
 
2
(F,OH)
 
2
9.AF.45Reinhardbraunsite
Ca
 
5
(SiO
 
4
)
 
2
(OH,F)
 
2
9.AF.45Kumtyubeite
Ca
 
5
(SiO
 
4
)
 
2
F
 
2
9.AF.45Hydroxylchondrodite
Mg
 
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.50Humite
(Mg,Fe
2+
 
)
 
7
(SiO
 
4
)
 
3
(F,OH)
 
2
9.AF.50Manganhumite
(Mn
2+
 
,Mg)
 
7
(SiO
 
4
)
 
3
(OH)
 
2
9.AF.50Unnamed (Ca-analogue of Humite)
Ca
 
7
(SiO
 
4
)
 
4
F
 
2
9.AF.55Clinohumite
(Mg,Fe
2+
 
)
 
9
(SiO
 
4
)
 
4
(F,OH)
 
2
9.AF.55Sonolite
Mn
2+
9
(SiO
 
4
)
 
4
(OH,F)
 
2
9.AF.55Hydroxylclinohumite
Mg
 
9
(SiO
 
4
)
 
4
(OH,F)
 
2
9.AF.60Leucophoenicite
Mn
2+
7
(SiO
 
4
)
 
3
(OH)
 
2
9.AF.65Ribbeite
(Mn
2+
 
,Mg)
 
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.70Jerrygibbsite
Mn
2+
9
(SiO
 
4
)
 
4
(OH)
 
2
9.AF.75Franciscanite
Mn
2+
6
(V
5+
 
,☐)
 
2
(SiO
 
4
)
 
2
(O,OH)
 
6
9.AF.75Örebroite
Mn
2+
3
(Fe
3+
 
,Sb
5+
 
)(SiO
 
4
)(O,OH)
 
3
9.AF.75Welinite
Mn
2+
6
(W
6+
 
,Mg)
 
2
(SiO
 
4
)
 
2
(O,OH)
 
6
9.AF.80Ellenbergerite
Mg
 
6
(Mg,Ti,Zr,◻)
 
2
(Al,Mg)
 
6
Si
 
8
O
 
28
(OH)
 
10
9.AF.85Chloritoid
(Fe
2+
 
,Mg,Mn
2+
 
)Al
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.85Magnesiochloritoid
MgAl
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.85Ottrélite
(Mn
2+
 
,Fe
2+
 
,Mg)Al
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.90Olmiite
CaMn
2+
 
[SiO
 
3
(OH)](OH)

Other Names for Poldervaartite

Synonyms:
IMA1992-012
Other Languages:
German:Poldervaartit
Russian:Полдерваартит
Spanish:Poldervaartita

Other Information

Fluorescence in UV light:Deep red in SW
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Poldervaartite

Reference List:

- +
Day, Y., Harlow G.E., and McGhie, A.R. (1993) American Mineralogist, 78, 1082-1087.

New Minerals (1997), New Minerals 1990-1994.

Bonazzi, P., Bindi, L., Medenbach, O., Pagano, R., Lampronti, Menchetti, S. (2007): Olmiite, CaMn[SiO3(OH)](OH), the Mn-dominant analogue of poldervaartite, a new mineral species from Kalahari manganese fields (Republic of South Africa), Mineralogical Magazine, 71, 193-291.

Internet Links for Poldervaartite

Search Engines:
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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Poldervaartite details from Handbook of Mineralogy (PDF)
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    • Localities for Poldervaartite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    Hide Locality List
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    South Africa
     
    • Northern Cape Province
      • Kalahari manganese fields
        • Hotazel
    		Amer.Min.(1993) 78, 1082-1087; von Bezing, L. & Gutzmer, J. (1994): Das Kalahari Manganerzfeld und seine Mineralien (II). Mineralien-Welt, 5(5), 41-59. Gutzmer, J. & Cairncross, B. (2001): Seltene Mineralien aus dem Kalahari-Manganerzfeld, Südafrika. Lapis, 26(10), 32-42; Gutzmer, J. & Cairncross, B. (2002): Spectacular Minerals from the Kalahari Manganese Field, South Africa. Rocks & Minerals, 77(2), 94-107.
        • Kuruman
          • N'Chwaning Mines
    		No reference listed
    • Cairncross, B., Gutzmer, J. & Pretorius, A. (2002): Spektakulärer Neufund: Poldervaartit aus der N'Chwaning II - Mine, Kalahari, Südafrika. Lapis, 27(5), 30-34; Bonazzi, P., Bindi, L., Medenbach, O., Pagano, R., Lampronti, Menchetti, S. (2007): Olmiite, CaMn[SiO3(OH)](OH), the Mn-dominant analogue of poldervaartite, a new mineral species from Kalahari manganese fields (Republic of South Africa), Mineralogical Magazine, 71, 193-291.. Pagano et al (2008) Mineralogical Record 39:373-381
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    Copyright © Jolyon Ralph and Ida Chau 1993-2013. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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