Crookesite Mineral Data (original) (raw)
General Crookesite Information
Chemical Formula:
Cu7(Tl,Ag)Se4
Composition:
Molecular Weight = 940.92 gm
Thallium 16.29 % Tl
Copper 47.28 % Cu
Silver 2.87 % Ag
Selenium 33.57 % Se
______
100.00 %
Empirical Formula:
Cu7Tl0.75Ag0.25Se4
Environment:
Of hydrothermal origin, with other selenides.
IMA Status:
Valid Species (Pre-IMA) 1866
Locality:
From Skrikerum, near Tryserum, Kalmar, Sweden. Link to MinDat.org Location Data.
Name Origin:
After Sir William Crookes (1832-1919), who discovered thallium.
Synonym:
ICSD 69104
PDF 41-1457
Crookesite Image
Images:
 |
Crookesite Eucairite Comments: Polished section (PPL) showing zoned crystal of cream-colored eucairite and pale lavender crookesite along with steel blue umangite and white clausthalite in dark gray gangue.. Location: Mine dump (tailings) of Shaft 371 near Hartenstein/Saxony, Germany.Scale: Picture size 5 mm. © Thomas Schlothauer |
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Crookesite Crystallography
Axial Ratios:
a:c = 1:0.37891
Cell Dimensions:
a = 10.435, c = 3.954, Z = 2; V = 430.55 Den(Calc)= 7.26
Crystal System:
Tetragonal - DisphenoidalH-M Symbol (4) Space Group: I 4
X Ray Diffraction:
By Intensity(I/Io): 2.59(1), 3.29(1), 3(0.8),
Crystal Structure:
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| | Eriksson L , Werner P E , Berger R , Meerschaut A , Journal of Solid State Chemistry , 90 (1991) p.61-68, Structure refinement of TlCu7Se4 from X-ray powder profile data, Locality: synthetic, Sample: GH, Note: Cell parameters are an average of Table 1 values View Additional jPOWD Structure files for Crookesite [1] [2] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
Physical Properties of Crookesite
Cleavage:
{???} Good
Color:
Blue gray, Brown pink, Gray.
Density:
6.9
Diaphaneity:
Opaque
Fracture:
Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Disseminated - Occurs in small, distinct particles dispersed in matrix.
Hardness:
2.5-3 - Finger Nail-Calcite
Luster:
Metallic
Optical Properties of Crookesite
RL Anisotrophism:
Weak but distinct, in brownish tones.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Crookesite in Air
| λ | R1 | R 2 |  |
∑ R1(λ) | ∑ R2(λ) |
|---|---|---|---|---|---|
| 400 nm | 33.00 | 37.30 |  |
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| 420 nm | 32.60 | 37.40 |  |
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| 440 nm | 32.20 | 37.50 |  |
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| 460 nm | 31.80 | 37.40 |  |
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| 480 nm | 31.40 | 37.30 |  |
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| 500 nm | 31.40 | 37.00 |  |
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| 520 nm | 31.50 | 36.70 |  |
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| 540 nm | 31.50 | 36.50 |  |
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| 560 nm | 31.60 | 36.50 |  |
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| 580 nm | 31.70 | 36.60 |  |
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| 600 nm | 31.90 | 36.80 |  |
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| 620 nm | 32.20 | 37.00 |  |
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| 640 nm | 32.30 | 37.40 |  |
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| 660 nm | 32.50 | 37.80 |  |
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| 680 nm | 32.70 | 38.20 |  |
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| 700 nm | 32.80 | 38.60 |  |
Calculated Relative Intensity Colors of Crookesite in Air
| RelativeIntensity | 0% | 30% | 60% | 90% | 100% | 120% | 150% | 180% | 210% | 240% | 270% | 280% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| R1 | ||||||||||||
| R2 |
Calculated Properties of Crookesite
Electron Density:
Bulk Density (Electron Density)=6.35 gm/cc
note: Specific Gravity of Crookesite =7.26 gm/cc.
Fermion Index:
Fermion Index = 0.02
Boson Index = 0.98
Photoelectric:
PECrookesite = 331.04 barns/electron
U=PECrookesite x rElectron Density=2,102.14 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Crookesite is Not Radioactive
Crookesite Classification
Dana Class:
02.04.12.01 (02)Sulfides - Including Selenides and Tellurides
(02.04)where Am Bn Xp, with (m+n):p=2:1
(02.04.12)Dana Group
02.04.12.01 Crookesite Cu7(Tl,Ag)Se4 I 4 4
02.04.12.02 Sabatierite Cu4TlSe3 P 4/mmm 4/m 2/m 2/m
Strunz Class:
02.BD.50 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
02.B - Metal Sulfides, M:S > 1:1 (mainly 2:1)
02.BD -With Hg, Tl
02.BD.50 Crookesite Cu7(Tl,Ag)Se4 I 4 4
Other Crookesite Information
References:
NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
See Also:
Links to other databases for Crookesite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
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Ask about Crookesite here :
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Print or Cut-and-Paste your Crookesite Specimen Label here :
Crookesite
Cu7(Tl,Ag)Se4
Dana No: 02.04.12.01 Strunz No: 02.BD.50
Locality:
Notes: