General Matildite Information
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 Chemical Formula: |
AgBiS2 |
| Composition: |
Molecular Weight = 380.98 gm |
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Silver 28.31 % Ag |
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Bismuth 54.85 % Bi |
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Sulfur 16.83 % S |
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______ |
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100.00 % |
| Empirical Formula: |
AgBiS2 |
| Environment: |
Moderate to high temperature hydrothermal deposts and in pegmatites. |
| IMA Status: |
Valid Species (Pre-IMA) 1883 |
| Locality: |
Matilda mine, near Moroccha, Provinence Junin, Peru. Link to MinDat.org Location Data. |
| Name Origin: |
Named after its locality |
| Name Pronunciation: |
Matildite + Pronunciation  |
| Synonym: |
Beegerite - mixture of schirmerite and matildite |
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ICSD 44340 |
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PDF 24-1031 |
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Schapbachite |
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Matildite Image |
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Images:
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Images:
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Matildite Bismuth Bismuthinite
Comments: SEM image of native Bi replaced by bismuthinite and matildite. Black areas represent gangue minerals. (CanMin, v43:899).
Location: Uranium deposit at Niederschlema-Alberoda, Germany.
Scale: See Image.
© Canadian Mineralogist |
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Matildite Crystallography
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| Axial Ratios: |
a:c = 1:4.66256 |
| Cell Dimensions: |
a = 4.066, c = 18.958, Z = 3; V = 271.43 Den(Calc)= 6.99 |
| Crystal System: |
Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: P 3m1 |
| X Ray Diffraction: |
By Intensity(I/Io): 2.827(1), 3.3(0.8), 2.03(0.6), |
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Crystal Structure:
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Geller S , Wernick J H , Acta Crystallographica , 12 (1959) p.46-54, Ternary semiconducting compounds with sodium chloride-like structure: AgSbSe2,, AgSbTe2, AgBiS2, AgBiSe2, Locality: synthetic, Sample: annealed at T = 152 C for t = 15 days
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Physical Properties of Matildite
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| Cleavage: |
None |
| Color: |
Gray, Iron black. |
| Density: |
6.9 |
| Diaphaneity: |
Opaque |
| Fracture: |
Brittle - Uneven - Very brittle fracture producing uneven fragments. |
| Habit: |
Acicular - Occurs as needle-like crystals. |
| Habit: |
Massive - Granular - Common texture observed in granite and other igneous rock. |
| Hardness: |
2.5 - Finger Nail |
| Luminescence: |
Non-fluorescent. |
| Luster: |
Metallic |
| Magnetism: |
Nonmagnetic |
| Streak: |
light gray |
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Optical Properties of Matildite
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| RL Anisotrophism: |
Weak. |
| RL Color: |
White. |
| RL Pleochroism: |
Weak. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Matildite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
41.40 |
47.20 | |
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| 420 nm |
41.90 |
47.80 |
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| 440 nm |
42.20 |
48.30 |
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| 460 nm |
43.10 |
48.80 |
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| 480 nm |
43.40 |
49.30 |
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| 500 nm |
43.40 |
49.30 |
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| 520 nm |
43.00 |
49.00 |
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| 540 nm |
42.80 |
48.40 |
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| 560 nm |
42.50 |
47.80 |
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| 580 nm |
42.20 |
47.30 |
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| 600 nm |
41.70 |
46.90 |
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| 620 nm |
41.30 |
46.70 |
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| 640 nm |
40.80 |
46.70 |
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| 660 nm |
40.30 |
46.70 |
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| 680 nm |
39.90 |
46.30 |
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| 700 nm |
39.30 |
46.10 |
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