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Mendozavilite-KCa
A valid IMA mineral species
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About Mendozavilite-KCa
Formula:
[K2(H2O)15Ca(H2O)6][Mo8P2Fe3+3O34(OH)3]
Colour:
Greenish yellow
Lustre:
Sub-Adamantine, Vitreous
Hardness:
2½
Crystal System:
Monoclinic
Member of:
Name:
Named for the relationship to other mendozavilite group minerals and the dominant cations K and Ca.
First recognized as a potential hypothetical member of the Betpakdalite group (IMA 10-E). Later in 2011, approved by IMA as a valid species.
Unique Identifiers
Mindat ID:
41947
Long-form identifier:
mindat:1:1:41947:1
Similar Names
| Mendozavilite-CaCa | A synonym of Melkovite |
IMA Classification of Mendozavilite-KCa
Approved
IMA Formula:
[K2(H2O)15Ca(H2O)6][Mo6+8P2Fe3+3O34(OH)3]
Approval year:
2011
First published:
2012
Type description reference:
Kampf, A. R., Mills, S. J., Rumsey, M. S., Dini, M., Birch, W. D., Spratt, J., Pluth, J. J., Steele, I. M., Jenkins, R. A., Pinch, W. W. (2012) The heteropolymolybdate family: structural relations, nomenclature scheme and new species. Mineralogical Magazine, 76 (5) 1175-1207 doi:10.1180/minmag.2012.076.5.09
Classification of Mendozavilite-KCa
7.GB.50
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
G : Molybdates, Wolframates and Niobates
B : With additional anions and/or H2O
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
G : Molybdates, Wolframates and Niobates
B : With additional anions and/or H2O
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Mdz-KCa | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Mendozavilite-KCa
Sub-Adamantine, Vitreous
Transparency:
Transparent
Colour:
Greenish yellow
Streak:
Very pale yellowish green
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Parting:
{001}
Fracture:
Irregular/Uneven
Optical Data of Mendozavilite-KCa
Type:
Biaxial (+)
RI values:
nα = 1.780(5) nβ = 1.795(5) nγ = 1.817
2V:
Measured: 80° (10)
Max. Birefringence:
δ = 0.037
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Dispersion:
r < v, strong
Pleochroism:
Non-pleochroic
Chemistry of Mendozavilite-KCa
Mindat Formula:
[K2(H2O)15Ca(H2O)6][Mo8P2Fe3+3O34(OH)3]
Element Weights:
| Element | % weight |
|---|---|
| O | 44.427 % |
Punta de Su Seinargiu, Sarroch, Metropolitan City of Cagliari, Sardinia, Italy