Cornetite
A valid IMA mineral species - grandfathered
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About Cornetite
Jules Cornet
Formula:
Cu3(PO4)(OH)3
Colour:
Dark blue to green-blue; green-blue in transmitted light.
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
4.10
Crystal System:
Orthorhombic
Name:
Named in honour of Mr Jules Cornet (4 March 1865, La Louvière, Belgium – 17 May 1929, Mons, Belgium), a Belgian geologist. He prospected in the Congo and particularly in Katanga, where he discovered its immense mineral wealth.
Cornetite was the first new mineral discovered in Congo.
Cornetite was the first new mineral discovered in Congo.
Type Locality:
This page provides mineralogical data about Cornetite.
Unique Identifiers
Mindat ID:
1131
Long-form identifier:
mindat:1:1:1131:6
Similar Names
| Carnatite | A synonym of 'Labradorite' | |
| Carnotite | A valid IMA mineral species - grandfathered | K2(UO2)2(VO4)2 · 3H2O |
| Carnotite (of Kroll) | A synonym of Silicocarnotite | |
| Corneite | A synonym of 'Biotite hornfels' | |
| Coronadite | A valid IMA mineral species - grandfathered | Pb(Mn64+Mn23+)O16 |
| Corundite | A rock subtype | |
| Garnetite | A rock classification type |
IMA Classification of Cornetite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Cu2+3PO4(OH)3
Classification of Cornetite
8.BE.15
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
41.3.2.1
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
3 : (AB)3(XO4)Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
3 : (AB)3(XO4)Zq
19.2.2
19 : Phosphates
2 : Phosphates of Cu
19 : Phosphates
2 : Phosphates of Cu
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 |
|---|---|---|
| Cne | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Cornetite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Cornetite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Dark blue to green-blue; green-blue in transmitted light.
Comment:
May exhibit colour zoning in shades of green-blue.
Hardness:
4½ on Mohs scale
Cleavage:
None Observed
Density:
4.10 g/cm3 (Measured) 4.14 g/cm3 (Calculated)
Optical Data of Cornetite
Type:
Biaxial (-)
RI values:
nα = 1.765 nβ = 1.81 nγ = 1.82
2V:
Measured: 33° , Calculated: 48°
Max. Birefringence:
δ = 0.055
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.
Dispersion:
none
Optical Extinction:
X = b; Y = a; Z = c.
Pleochroism:
Non-pleochroic
Chemistry of Cornetite
Mindat Formula:
Cu3(PO4)(OH)3
Element Weights:
Elements listed:
Common Impurities:
Co
Crystallography of Cornetite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pbca
Cell Parameters:
a = 10.88 Å, b = 14.1 Å, c = 7.11 Å
Ratio:
a:b:c = 0.772 : 1 : 0.504
Unit Cell V:
1,090.73 ų (Calculated from Unit Cell)
Morphology:
Crystals short prismatic [001] to equant. Face {210} commonly rounded. May also show large {021}, {221}. Crusts of minute crystals.
Twinning:
Reported on {h0l}.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
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CIF File Best | x | y | z | a | b | c
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0014624 | Cornetite | Eby R K, Hawthorne F C (1989) Cornetite: modulated densely-packed Cu2+ oxysalt Mineralogy and Petrology 40 127-136 | 1989 | Mine de L'Etoile, Katanga, Zaire | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.07 Å | (60) |
| 5.48 Å | (50) |
| 4.55 Å | (30) |
| 4.29 Å | (90) |
| 3.68 Å | (70) |
| 3.17 Å | (80) |
| 3.04 Å | (100) |
| 2.95 Å | (50) |
| 2.74 Å | (30) |
| 2.54 Å | (30) |
| 2.44 Å | (30) |
| 2.15 Å | (30) |
| 2.06 Å | (70) |
| 1.574 Å | (40) |
| 1.545 Å | (40) |
| 1.509 Å | (30) |
Comments:
Bwana Mkubwa, Zambia. Data from Berry (1950).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Cornetite
General Appearance of Type Material:
Blue crystals, either isolated or grouped, on sandstone. Square prisms with ocathedral terminations.
Place of Conservation of Type Material:
Laboratory of Mineralogy, University of Liège, Belgium, 9.130 and 9.133.
Geological Setting of Type Material:
Oxidized zone of a hydrothermal copper deposit.
Associated Minerals at Type Locality:
Other Language Names for Cornetite
Common Associates
Associations Based on Photo Data:
| 138 photos of Cornetite associated with Malachite | Cu2(CO3)(OH)2 |
| 92 photos of Cornetite associated with Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| 55 photos of Cornetite associated with Pseudomalachite | Cu5(PO4)2(OH)4 |
| 45 photos of Cornetite associated with Heterogenite | Co3+O(OH) |
| 25 photos of Cornetite associated with Libethenite | Cu2(PO4)(OH) |
| 17 photos of Cornetite associated with Baryte | BaSO4 |
| 17 photos of Cornetite associated with Goethite | Fe3+O(OH) |
| 2 photos of Cornetite associated with 'Duhamelite' | (Pb,Bi,Ca)Cu(VO4)(OH,O) |
| 2 photos of Cornetite associated with Khorixasite | (Bi0.67◻0.33)Cu(VO4)(OH) |
| 1 photo of Cornetite associated with 'Sandstone' |
Related Minerals - Strunz-mindat Grouping
| 8.BE.05 | Augelite | Al2(PO4)(OH)3 |
| 8.BE.10 | Grattarolaite | Fe3+3(PO4)O3 |
| 8.BE.20 | Clinoclase | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Gilmarite | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Arhbarite | Cu2Mg(AsO4)(OH)3 |
| 8.BE.30 | Flinkite | Mn2+2Mn3+(AsO4)(OH)4 |
| 8.BE.30 | Argandite | Mn7(VO4)2(OH)8 |
| 8.BE.30 | Raadeite | Mg7(PO4)2(OH)8 |
| 8.BE.30 | Allactite | Mn2+7(AsO4)2(OH)8 |
| 8.BE.35 | 'Mineral E (of Dunn, et. al., 1982)' | |
| 8.BE.35 | Chlorophoenicite | (Mn,Mg)3Zn2(AsO4)(OH,O)6 |
| 8.BE.35 | Magnesiochlorophoenicite | (Mg,Mn)3Zn2(AsO4)(OH,O)6 |
| 8.BE.40 | Gerdtremmelite | (Zn,Fe)(Al,Fe)2(AsO4)(OH)5 |
| 8.BE.45 | Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 |
| 8.BE.45 | Mcgovernite | Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21 |
| 8.BE.45 | Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x |
| 8.BE.45 | Carlfrancisite | Mn2+3(Mn2+,Mg,Fe3+,Al)42[As3+O3]2(As5+O4)4[(Si,As5+)O4]6[(As5+,Si)O4]2(OH)42 |
| 8.BE.45 | Arakiite | (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 |
| 8.BE.50 | Synadelphite | Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O |
| 8.BE.55 | Holdenite | (Mn2+,Mg)6Zn3(AsO4)2(SiO4)(OH)8 |
| 8.BE.60 | Kolicite | Mn2+7Zn4(AsO4)2(SiO4)2(OH)8 |
| 8.BE.65 | Sabelliite | (Cu,Zn)2Zn(AsO4,SbO4)(OH)3 |
| 8.BE.70 | Jarosewichite | Mn2+3Mn3+(AsO4)(OH)6 |
| 8.BE.75 | Theisite | Cu5Zn5(AsO4,SbO4)2(OH)14 |
| 8.BE.80 | Coparsite | Cu4(AsO4,VO4)O2Cl |
| 8.BE.85 | Waterhouseite | Mn2+7(PO4)2(OH)8 |
| 8.BE.90 | Vasilseverginite | Cu9O4(AsO4)2(SO4)2 |
Other Information
Notes:
Soluble in cold HCl.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Cornetite
mindat.org URL:
https://www.mindat.org/min-1131.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Cornetite
Reference List:
Hutchinson, A., MacGregor, A. M. (1921) On Cornetite from Bwana Mkubwa, Northern Rhodesia. Mineralogical Magazine and Journal of the Mineralogical Society, 19 (95). 225-232 doi:10.1180/minmag.1921.019.95.01
Larsen, E.S.; Berman, H. (1934) The microscopic determination of the nonopaque minerals. Bulletin of the US Geological Survey Vol. 848. US Geological Survey p.1-266. doi:10.3133/b848 p.201
Richmond, Wallace E. (1940) Crystal chemistry of the phosphates, arsenates and vanadates of the type A2XO4(Z). American Mineralogist, 25 (7). 441-479
Fehlmann, M., Ghose, Subrata, Finney, J. J. (1964) Direct Determination of the Crystal Structure of Cornetite, Cu3PO4(OH)3, by the Monte Carlo Method. The Journal of Chemical Physics, 41 (7) 1910-1916 doi:10.1063/1.1726182
Ramanaiah, M. Venkata; Ravikumar, R. V. S. S. N.; Srinivasulu, G.; Reddy, B. J.; Rao, P. S. (1996) Detailed spectroscopic studies on cornetite from southern shaba, zaire. Ferroelectrics, 175 (1). 175-182 doi:10.1080/00150199608213386
Frost, Ray L., Williams, Peter A., Martens, Wayde, Kloprogge, J. Theo, Leverett, Peter (2002) Raman spectroscopy of the basic copper phosphate minerals cornetite, libethenite, pseudomalachite, reichenbachite and ludjibaite. Journal of Raman Spectroscopy, 33 (4). 260-263 doi:10.1002/jrs.850
Martens, Wayde, Frost, Ray L. (2003) An infrared spectroscopic study of the basic copper phosphate minerals: Cornetite, libethenite, and pseudomalachite. American Mineralogist, 88 (1) 37-46 doi:10.2138/am-2003-0105
Kharbish, Sherif, Andráš, Peter, Luptáková, Jarmila, Milovská, Stanislava (2014) Raman spectra of oriented and non-oriented Cu hydroxy-phosphate minerals: Libethenite, cornetite, pseudomalachite, reichenbachite and ludjibaite. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 130. 152-163 doi:10.1016/j.saa.2014.01.144
Localities for Cornetite
Showing 40 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Australia | |
| Museum Victoria Mineralogy Collection |
| Crane et al. (2001) |
| Munro-Smith (2006) +1 other reference |
| Sorrell (n.d.) |
| Kim Macdonald |
Chile | |
| C. Lemanski collection (7198 & 7201CL) |
| boyuan zhang Collection |
| maurizio dini collection - analysed ... |
| C. Ruiz Fuller/F. Peebles (1988) |
| samples analysed by Dr. Hubert Putz |
DR Congo | |
| |
| Museum of Victoria specimen No. M ... +1 other reference |
| Lhoest (1992) |
| De Bondt (n.d.) | |
| Palache et al. (1951) +1 other reference |
| Mambwe et al. (Ruashi Cu-Co Deposit) | |
| L. Kruszewski collection |
| Lhoest (1992) |
| Wilson (2018) |
Germany | |
| Weiß (1990) |
| Weiß (1990) | |
Morocco | |
| Favreau (n.d.) +1 other reference |
Namibia | |
| SEM-EDS analysed by Georges Favreau (photo ID 1214009) |
Russia | |
| Gongalsky et al. (2019) |
South Africa | |
| Thomas Kleser Collection +2 other references |
Spain | |
| Bocamina (4) |
| Calvo Rebollar et al. (2024) |
| Joan Abella i Creus (Joanabellacreus@gmail.com) |
USA | |
| Khin (1970) +1 other reference |
| Anthony et al. (1995) |
| Eckel et al. (1997) |
| Palache et al. (1951) +2 other references |
| Castor et al. (2004) |
| Castor et al. (2004) | |
| Palache et al. (1951) | |
| +4 other references |
| NBMG Bull 70 Geology and Mineral ... |
| Freeport-McMoRan |
Zambia | |
| Hutchinson et al. (1921) +1 other reference |
| MacIntyre (2019) |
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L'Etoile du Congo Mine, Lubumbashi, Haut-Katanga, DR Congo