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Correianevesite
A valid IMA mineral species
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About Correianevesite
Prof. Correia Neves
Formula:
Fe2+Mn2+2(PO4)2 · 3H2O
Colour:
Grayish-brown to reddish-brown
Lustre:
Vitreous
Hardness:
3½
Specific Gravity:
3.25
Crystal System:
Orthorhombic
Member of:
Name:
Named in honour of Professor José Marques Correia Neves (1929-2011), mineralogist from Portugal, for his detailed studies of Brazilian pegmatites.
Practically a cation-ordered, intermediate member of the Phosphoferrite-Reddingite Series.
Reddingite group (Chukanov et al. 2013)
Reddingite group (Chukanov et al. 2013)
Unique Identifiers
Mindat ID:
43669
Long-form identifier:
mindat:1:1:43669:0
IMA Classification of Correianevesite
Approved
IMA Formula:
Fe2+Mn2+2(PO4)2·3H2O
Approval year:
2013
First published:
2014
Type description reference:
Chukanov, N. V., Scholz, R., Zubkova, N. V., Pekov, I. V., Belakovskiy, D. I., Van, K. V., Lagoeiro, L., Graca, L. M., Krambrock, K., de Oliveira, L. C. A., Filho, L. A. D. M., Chaves, M. L. S. C., Pushcharovsky, D. Y. (2014) Correianevesite, Fe2+Mn2+2(PO4)2·3H2O, a new reddingite-group mineral from the Cigana mine, Conselheiro Pena, Minas Gerais, Brazil. American Mineralogist, 99 (4) 811-816 doi:10.2138/am.2014.4709
Classification of Correianevesite
8.CC.
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
C : With only medium-sized cations, RO4:H2O = 1:1.5
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
C : With only medium-sized cations, RO4:H2O = 1:1.5
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 |
|---|---|---|
| Corr | 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 Correianevesite
Vitreous
Transparency:
Transparent
Colour:
Grayish-brown to reddish-brown
Streak:
White
Hardness:
3½ on Mohs scale
Cleavage:
Poor/Indistinct
on (010).
on (010).
Fracture:
Irregular/Uneven
Comment:
Fracture is laminated, uneven across cleavage.
Density:
3.25(2) g/cm3 (Measured) 3.275 g/cm3 (Calculated)
Optical Data of Correianevesite
Type:
Biaxial (+)
RI values:
nα = 1.661(5) nβ = 1.673(5) nγ = 1.703(5)
2V:
Measured: 70° (10), Calculated: 65.6°
Max. Birefringence:
δ = 0.042
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:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Chemistry of Correianevesite
Mindat Formula:
Fe2+Mn2+2(PO4)2 · 3H2O
Element Weights:
Crystallography of Correianevesite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 9.4887(2) Å, b = 10.1149(2) Å, c = 8.7062(2) Å
Ratio:
a:b:c = 0.938 : 1 : 0.861
Unit Cell V:
835.6 ų
Z:
4
Morphology:
Bipyramidal crystals
Comment:
Pbna
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.08 Å | (43) |
| 4.314 Å | (28) |
| 3.220 Å | (100) |
| 3.125 Å | (20) |
| 2.756 Å | (35) |
| 2.686 Å | (25) |
| 2.436 Å | (22) |
| 2.233 Å | (23) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Correianevesite
General Appearance of Type Material:
As grayish-brown to reddish-brown transparent bipyramidal crystals up to 4 mm in size.
Place of Conservation of Type Material:
Type material is deposited in the collections of the collections of the Museu de Ciência Tecnica, Escola de Minas, Universidade Federal de Ouro Preto, Praça Tiradentes, Ouro Preto, Brazil, registration number SAA-081B
Geological Setting of Type Material:
A phosphate-rich granite pegmatite.
Associated Minerals at Type Locality:
Reference:
Chukanov, N. V., Scholz, R., Zubkova, N. V., Pekov, I. V., Belakovskiy, D. I., Van, K. V., Lagoeiro, L., Graca, L. M., Krambrock, K., de Oliveira, L. C. A., Filho, L. A. D. M., Chaves, M. L. S. C., Pushcharovsky, D. Y. (2014) Correianevesite, Fe2+Mn2+2(PO4)2·3H2O, a new reddingite-group mineral from the Cigana mine, Conselheiro Pena, Minas Gerais, Brazil. American Mineralogist, 99 (4) 811-816 doi:10.2138/am.2014.4709
Cigana claim, Barra do Cuieté, Conselheiro Pena, Minas Gerais, Brazil