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Mcconnellite
A valid IMA mineral species
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About Mcconnellite
Richard B. McConnell
Formula:
CuCrO2
Colour:
Deep red
Hardness:
5½
Specific Gravity:
5.49
Crystal System:
Trigonal
Member of:
Name:
Named in 1967 by Charles Milton, Daniel E. Appleman, Edward Ching-Te Chao, Frank Cuttita, Joseph I. Dinnin, Edward J. Dwornik, Margaret Hall, Blanche L. Ingram, and Harry J. Rose, Jr. in honor of Dr. Richard Bradford McConnell (27 December 1903, Ottawa, Ontario, Canada - 6 August 1986, Sussex, England), former Director, British Guyana Geological Survey.
As with other Cr mineral species from the Merume River locality, such as bracewellite, grimaldiite, and guyanaite, this species is NOT universally present in every specimen and verification of each specimen is required.
Unique Identifiers
Mindat ID:
2612
Long-form identifier:
mindat:1:1:2612:9
IMA Classification of Mcconnellite
Approved
IMA Formula:
Cu1+Cr3+O2
Approval year:
1967
First published:
1976
Classification of Mcconnellite
4.AB.15
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
A : Metal: Oxygen = 2:1 and 1:1
B : M:O = 1:1 (and up to 1:1.25); with small to medium-sized cations only
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
A : Metal: Oxygen = 2:1 and 1:1
B : M:O = 1:1 (and up to 1:1.25); with small to medium-sized cations only
7.1.1.2
7 : MULTIPLE OXIDES
1 : ABX2
7 : MULTIPLE OXIDES
1 : ABX2
7.14.7
7 : Oxides and Hydroxides
14 : Oxides of Cr
7 : Oxides and Hydroxides
14 : Oxides of Cr
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 |
|---|---|---|
| Mcn | 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 Mcconnellite
Transparency:
Translucent
Colour:
Deep red
Hardness:
5½ on Mohs scale
Cleavage:
Perfect
{0001}
{0001}
Density:
5.49 g/cm3 (Measured) 5.609 g/cm3 (Calculated)
Chemistry of Mcconnellite
Mindat Formula:
CuCrO2
Element Weights:
Elements listed:
Crystallography of Mcconnellite
Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
R3m
Cell Parameters:
a = 2.97 Å, c = 17.11 Å
Ratio:
a:c = 1 : 5.761
Unit Cell V:
130.71 ų (Calculated from Unit Cell)
Z:
1
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.85 Å | (medium strong) |
| 2.462 Å | (medium strong) |
| 2.21 Å | (very weak) |
| 1.420 Å | (very weak) |
| 1.64 Å | (very very weak) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 56 : Slag and smelter minerals (see also #51 and #55) |
Type Occurrence of Mcconnellite
General Appearance of Type Material:
Tabular deep-red rhombohedral crystals up to 1 mm in size, that are polyphase with grimaldiite. Occur with other minerals forming black rounded grains.
Place of Conservation of Type Material:
Natural History Museum, London, United Kingdom, number BM 1979,136.
National Museum of Natural History (Smithsonian Institution), Washington, D.C., USA.
National Museum of Natural History (Smithsonian Institution), Washington, D.C., USA.
Geological Setting of Type Material:
Alluvial gravels.
Associated Minerals at Type Locality:
Synonyms of Mcconnellite
Other Language Names for Mcconnellite
Relationship of Mcconnellite to other Species
Member of:
Other Members of Delafossite Group:
| Delafossite | Cu+Fe3+O2 | Trig. 3m(32/m) : R3m |
Structurally related to group(s):
Common Associates
Associations Based on Photo Data:
| 3 photos of Mcconnellite associated with Grimaldiite | CrO(OH) |
| 1 photo of Mcconnellite associated with Eskolaite | Cr2O3 |
| 1 photo of Mcconnellite associated with Native Gold | Au |
Related Minerals - Strunz-mindat Grouping
| 4.AB. | 'Carbon Monoxide Ice' | CO |
| 4.AB.05 | Crednerite | Cu+Mn3+O2 |
| 4.AB.10 | Tenorite | CuO |
| 4.AB.15 | Delafossite | Cu+Fe3+O2 |
| 4.AB.20 | Bromellite | BeO |
| 4.AB.20 | Zincite | ZnO |
| 4.AB.25 | Bunsenite | NiO |
| 4.AB.25 | Periclase | MgO |
| 4.AB.25 | Lime | CaO |
| 4.AB.25 | Manganosite | MnO |
| 4.AB.25 | Monteponite | CdO |
| 4.AB.25 | Wüstite | FeO |
| 4.AB.30 | Palladinite | PdO |
| 4.AB.35 | 'Hongquiite' | TiO |
Other Information
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 Mcconnellite
mindat.org URL:
https://www.mindat.org/min-2612.html
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References for Mcconnellite
Reference List:
Stroupe, James D. (1949) An X-Ray Diffraction Study of the Copper Chromites and of the “Copper-Chromium Oxide” Catalyst. Journal Of The American Chemical Society, 71 (2) 569-572 doi:10.1021/ja01170a052
Dannhauser, Walter, Vaughan, Philip A. (1955) The Crystal Structure of Cuprous Chromite. Journal Of The American Chemical Society, 77 (4) 896-897 doi:10.1021/ja01609a024
Localities for Mcconnellite
Showing 4 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.
Germany | |
| Gerhard Möhn Collection Analyzed by ... |
Guyana (TL) | |
| Geological Society of America (1967) +2 other references |
Jordan | |
|
Merume River, Rest of Region 8, Potaro-Siparuni Region, Guyana