Crookesite
A valid IMA mineral species - grandfathered
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About Crookesite
William Crookes
Formula:
Cu7(Tl, Ag)Se4
Formely considered (Cu,Tl,Ag)2Se.
Colour:
Lead Grey
Lustre:
Metallic
Hardness:
2½ - 3
Specific Gravity:
6.90
Crystal System:
Tetragonal
Name:
Named in honor of Sir William Crookes (17 June 1832, London, England - 4 April 1919, London, England), chemist and physicist. He worked on spectroscopy, and used that technology to discover thallium in 1861.
Type Locality:
This page provides mineralogical data about Crookesite.
Unique Identifiers
Mindat ID:
1159
Long-form identifier:
mindat:1:1:1159:0
Similar Names
| Crocoisite | A synonym of Crocoite |
IMA Classification of Crookesite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Cu1+7Tl1+Se2-4
First published:
1867
Classification of Crookesite
2.BD.50
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
B : Metal Sulfides, M: S > 1: 1 (mainly 2: 1)
D : With Hg, Tl
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
B : Metal Sulfides, M: S > 1: 1 (mainly 2: 1)
D : With Hg, Tl
2.4.12.1
2 : SULFIDES
4 : AmBnXp, with (m+n):p = 2:1
2 : SULFIDES
4 : AmBnXp, with (m+n):p = 2:1
3.5.12
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
5 : Sulphides etc. of Hg and Tl
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
5 : Sulphides etc. of Hg and Tl
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Crk | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Crk | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Crookesite
Metallic
Transparency:
Opaque
Colour:
Lead Grey
Hardness:
2½ - 3 on Mohs scale
Hardness:
VHN100=92 - 123 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
Distinct/Good
Two at right angles
Two at right angles
Density:
6.90 g/cm3 (Measured) 7.443 g/cm3 (Calculated)
Optical Data of Crookesite
Anisotropism:
Weak but distinct in brownish tones
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 400nm | 33.6% | 35.9% |
| 420nm | 33.3% | 35.8% |
| 440nm | 32.7% | 35.8% |
| 460nm | 32.4% | 35.7% |
| 480nm | 32.5% | 35.6% |
| 500nm | 32.8% | 35.3% |
| 520nm | 33.1% | 35.1% |
| 540nm | 33.1% | 34.8% |
| 560nm | 33.0% | 34.7% |
| 580nm | 32.7% | 34.6% |
| 600nm | 32.6% | 34.7% |
| 620nm | 32.4% | 35.0% |
| 640nm | 32.2% | 35.2% |
| 660nm | 31.9% | 35.2% |
| 680nm | 31.6% | 35.3% |
| 700nm | 31.2% | 35.3% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 35.9%.
R1 shown in black, R2 shown in red
Chemistry of Crookesite
Mindat Formula:
Cu7(Tl, Ag)Se4
Formely considered (Cu,Tl,Ag)2Se.
Formely considered (Cu,Tl,Ag)2Se.
Element Weights:
Elements listed:
Common Impurities:
Fe
Crystallography of Crookesite
Crystal System:
Tetragonal
Cell Parameters:
a = 10.435 Å, c = 3.954 Å
Ratio:
a:c = 1 : 0.379
Unit Cell V:
430.55 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Disseminated specks and in veinlets.
Comment:
Point Group: 4/m, 4, or 4 ; Space Group: I4/m, I4, or I4.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0013693 | Crookesite | Eriksson L, Werner P E, Berger R, Meerschaut A (1991) Structure refinement of TlCu7Se4 from X-ray powder profile data Journal of Solid State Chemistry 90 61-68 | 1991 | Skrikerum mine, Sweden | 0 | 293 | |
| 0013692 | Crookesite | Eriksson L, Werner P E, Berger R, Meerschaut A (1991) Structure refinement of TlCu7Se4 from X-ray powder profile data Journal of Solid State Chemistry 90 61-68 | 1991 | synthetic | 0 | 293 | |
| 0013691 | Crookesite | Eriksson L, Werner P E, Berger R, Meerschaut A (1991) Structure refinement of TlCu7Se4 from X-ray powder profile data Journal of Solid State Chemistry 90 61-68 | 1991 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.29 Å | (100) |
| 2.59 Å | (100) |
| 3.00 Å | (80) |
| 2.11 Å | (50) |
| 1.833 Å | (40) |
| 1.779 Å | (40) |
| 2.32 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Crookesite
General Appearance of Type Material:
As finely divided, disseminated specks.
Geological Setting of Type Material:
Hydrothermal deposits
Associated Minerals at Type Locality:
Other Language Names for Crookesite
Dutch:Crookesiet
German:Crookesit
Russian:Крукесит
Simplified Chinese:硒铊银铜矿
Spanish:Crookesita
Traditional Chinese:硒鉈銅銀礦
Common Associates
Associations Based on Photo Data:
| 41 photos of Crookesite associated with Calcite | CaCO3 |
| 21 photos of Crookesite associated with 'Thucholite' | |
| 20 photos of Crookesite associated with Eucairite | AgCuSe |
| 17 photos of Crookesite associated with Klockmannite | CuSe |
| 13 photos of Crookesite associated with Clausthalite | PbSe |
| 9 photos of Crookesite associated with Bukovite | (Cu3Fe)Σ4Tl2Se4 |
| 9 photos of Crookesite associated with Umangite | Cu3Se2 |
| 5 photos of Crookesite associated with Acanthite | Ag2S |
| 5 photos of Crookesite associated with Siderite | FeCO3 |
| 4 photos of Crookesite associated with Berzelianite | Cu2-xSe (x ≈ 0.12) |
Related Minerals - Strunz-mindat Grouping
| 2.BD. | Vrančiceite | Cu10Hg3S8 |
| 2.BD. | 'UM2004-33-S:AgCuHgSe' | (Ag,Cu)8Hg3(S,Se)7 |
| 2.BD.05 | Imiterite | Ag2HgS2 |
| 2.BD.10 | Gortdrumite | Cu24Fe2Hg9S23 |
| 2.BD.15 | Danielsite | (Cu,Ag)14HgS8 |
| 2.BD.15 | Balkanite | Cu9Ag5HgS8 |
| 2.BD.20 | Donharrisite | Ni3HgS3 |
| 2.BD.25 | Carlinite | Tl2S |
| 2.BD.30 | Bukovite | (Cu3Fe)Σ4Tl2Se4 |
| 2.BD.30 | Thalcusite | Tl2Cu3FeS4 |
| 2.BD.30 | Murunskite | K2(Cu,Fe)4S4 |
| 2.BD.35 | Rohaite | (Tl,Pb,K)2Cu8.7Sb2S4 |
| 2.BD.40 | Chalcothallite | Tl2(Cu,Fe)6SbS4 |
| 2.BD.45 | Sabatierite | TlCu6Se4 |
| 2.BD.55 | Brodtkorbite | Cu2HgSe2 |
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 Crookesite
mindat.org URL:
https://www.mindat.org/min-1159.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Crookesite
Reference List:
Earley, J. W. (1950) Description and synthesis of the selenide minerals. American Mineralogist, 35 (5-6) 337-364
Ramdohr, Paul (1969) The Ore Minerals and their Intergrowths. Pergamon Press, Oxford. 1174pp. doi:10.1016/c2013-0-10027-x
Jambor, John L.; Bladh, Kenneth W.; Ercit, T. Scott; Grice, Joel D.; Grew, Edward S. (1988) New mineral names. American Mineralogist, 73 (7-8). 927-935
Jambor, John L., Burke, Ernst A. J. (1989) New Mineral Names. American Mineralogist, 74 (11-12) 1399-1404
Localities for Crookesite
Showing 20 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.
Argentina | |
| Paar et al. (2002) +2 other references |
Armenia | |
| Khachaturyan (1957) |
Canada | |
| Mineralogical Society of America - ... +1 other reference |
China | |
| Chen et al. (2007) |
| Zhao et al. (1999) | |
Czech Republic | |
| Škácha et al. (2017) |
| Sejkora et al. (2024) |
| Sejkora et al. (2024) |
| Kvaček (1979) +1 other reference |
| American Mineralogist 73:933 +2 other references |
| Kvaček (1979) | |
France | |
| Agrinier et al. (1967) |
Germany | |
| Weiß (1990) |
| Weiß (1990) |
| Forster et al. (2004) |
Sweden (TL) | |
| Earley (1950) +2 other references |
Switzerland | |
| Stalder et al. (1998) |
| Stalder et al. (1998) |
UK | |
| Rumsey et al. (2015) |
USA | |
| personal correspondence with Doug Scott |
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Skrikerum Mine, Valdemarsvik, Östergötland County, Sweden