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Twinnite Mineral Data
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General Twinnite Information
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 Chemical Formula: |
Pb(Sb,As)2S4 |
| Composition: |
Molecular Weight = 574.28 gm |
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Antimony 40.28 % Sb |
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Arsenic 1.30 % As |
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Lead 36.08 % Pb |
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Sulfur 22.33 % S |
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______ |
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100.00 % |
| Empirical Formula: |
PbSb1.9As0.1S4 |
| Environment: |
In marble with other lead sulfantimonides. |
| IMA Status: |
Valid Species (Pre-IMA) 1957 |
| Locality: |
Madoc, Ontario, Canada. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Robert M. Thompson (1918-1967), Canadian Mineralogist: Thompson means "son of Thomas," which is Aramaic for "twin." |
| Name Pronunciation: |
Twinnite  |
| Synonym: |
IMA1966-017 |
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Twinnite Crystallography
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| Axial Ratios: |
a:b:c =2.4537:1:1.073 |
| Cell Dimensions: |
a = 19.583, b = 7.981, c = 8.564, Z = 8; alpha = 89.767°, beta = 89.617°, gamma = 90.267° V = 1,338.43 Den(Calc)= 5.70 |
| Crystal System: |
Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1 |
| X Ray Diffraction: |
By Intensity(I/Io): 3.51(1), 2.344(0.8), 2.78(0.7), |
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Physical Properties of Twinnite
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| Cleavage: |
{100} Perfect |
| Color: |
Black. |
| Density: |
5.26 |
| Diaphaneity: |
Opaque |
| Fracture: |
Brittle - Generally displayed by glasses and most non-metallic minerals. |
| Habit: |
Microscopic Crystals - Crystals visible only with microscopes. |
| Habit: |
Twinning Common - Crystals are usually twinned. |
| Hardness: |
3.5 - Copper Penny |
| Luster: |
Metallic |
| Streak: |
brownish black |
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Optical Properties of Twinnite
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| RL Color: |
White. |
| RL Pleochroism: |
Strong, displaying twin lamellae. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Twinnite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
39.10 |
45.20 |
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| 420 nm |
38.20 |
44.70 |
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| 440 nm |
37.30 |
44.20 |
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| 460 nm |
36.60 |
43.70 |
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| 480 nm |
36.20 |
43.20 |
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| 500 nm |
35.80 |
42.90 |
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| 520 nm |
35.50 |
42.50 |
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| 540 nm |
35.00 |
42.00 |
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| 560 nm |
34.40 |
41.40 |
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| 580 nm |
34.00 |
40.80 |
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| 600 nm |
33.50 |
40.00 |
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| 620 nm |
33.20 |
39.40 |
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| 640 nm |
32.80 |
38.70 |
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| 660 nm |
32.30 |
38.10 |
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| 680 nm |
31.70 |
37.50 |
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| 700 nm |
31.00 |
37.00 |
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Calculated Relative Intensity Colors of Twinnite in Air
Relative
Intensity |
0% |
30% |
60% |
90% |
100% |
120% |
150% |
180% |
210% |
240% |
270% |
| R1 |
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| R2 |
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Calculated Properties of Twinnite
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| Electron Density: |
Bulk Density (Electron Density)=4.89 gm/cc
note: Specific Gravity of Twinnite =5.70 gm/cc.
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| Fermion Index: |
Fermion Index = 0.08
Boson Index = 0.92 |
| Photoelectric: |
PETwinnite = 786.44 barns/electron
U=PETwinnite x rElectron Density=3,843.57 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Twinnite is Not Radioactive |
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Twinnite Classification
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| Dana Class: |
03.07.08.03 (03)Sulfides - Sulfosalts |
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(03.07)where z/y = 2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals |
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(03.07.08)Sartorite Group |
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03.07.08.01 Sartorite PbAs2S4 P 21/c 2/m |
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03.07.08.02 Guettardite Pb(Sb,As)2S4 P 21/a 2/m |
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03.07.08.03 Twinnite Pb(Sb,As)2S4 P1 1 |
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03.07.08.04 Marumoite! Pb32As40S92 P 21 2 |
| Strunz Class: |
02.HC.05a 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf |
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02.H - Sulfosalts of SnS Archetype |
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02.HC -With only Pb |
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02.HC.05a Guettardite Pb(Sb,As)2S4 P 21/a 2/m |
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02.HC.05a Sartorite PbAs2S4 P 21/c 2/m |
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02.HC.05a Twinnite Pb(Sb,As)2S4 P1 1 |
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Other Twinnite Information
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| References: |
NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1) |
| See Also: |
Links to other databases for Twinnite :
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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Print or Cut-and-Paste your Twinnite Specimen Label here :
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Twinnite
Pb(Sb,As)2S4
Dana No: 03.07.08.03 Strunz No: 02.HC.05a
Locality:
Notes:
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