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Alacranite Mineral Data
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General Alacranite Information
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 Chemical Formula: |
As8S9 |
| Composition: |
Molecular Weight = 887.97 gm |
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Arsenic 67.50 % As |
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Sulfur 32.50 % S |
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______ |
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100.00 % |
| Empirical Formula: |
As8S9 |
| Environment: |
Occurs as a cement in a sandy gravel (Uson caldera, USSR); in hydrothermal As-S veins (Alacran deposit, Chile). |
| IMA Status: |
Approved IMA 1986 |
| Locality: |
In the Uson caldera, Kamchatka, USSR. From the Alacran deposit, Pampa Larga, Chile. Link to MinDat.org Location Data. |
| Name Origin: |
For the occurrence in the Alacran deposit, Chile. |
| Name Pronunciation: |
Alacranite + Pronunciation  |
| Synonym: |
ICSD 42387 |
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PDF 42-537 |
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Alacranite Image |
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Images:
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Alacranite Crystallography
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| Axial Ratios: |
a:b:c =1.0355:1:0.9559 |
| Cell Dimensions: |
a = 9.942, b = 9.601, c = 9.178, Z = 2; beta = 101.94° V = 857.12 Den(Calc)= 3.44 |
| Crystal System: |
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2/c |
| X Ray Diffraction: |
By Intensity(I/Io): 2.9319(1)(222), 5.8638(0.89)(111), 3.0493(0.87)(221),5.0927(0.71)(111), 3.2791(0.69)(022), 3.0719(0.68)(310), 4.0307(0.58)(112), |
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Physical Properties of Alacranite
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| Cleavage: |
{???} Indistinct |
| Color: |
Red, Orange yellow. |
| Density: |
3.4 - 3.46, Average = 3.43 |
| Diaphaneity: |
Transparent |
| Habit: |
Equant Grains - Granular material with equel dimensions in x, y, and z. |
| Habit: |
Euhedral Crystals - Occurs as well-formed crystals showing good external form. |
| Hardness: |
1.5 - Between Talc and Gypsum |
| Luster: |
Adamantine - Greasy |
| Streak: |
orange |
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Optical Properties of Alacranite
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| Optical Data: |
Biaxial (+), a=2.39, g=2.52, bire=0.1300 |
| Pleochroism (x): |
orange yellow. |
| Pleochroism (y): |
orange yellow. |
| Pleochroism (z): |
orange yellow. |
| RL Color: |
Light gray with rose-yellow internal reflections. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Alacranite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
13.00 |
14.00 |
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| 425 nm |
13.20 |
14.60 |
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| 450 nm |
13.30 |
14.80 |
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| 475 nm |
13.40 |
14.80 |
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| 500 nm |
13.30 |
14.50 |
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| 525 nm |
13.10 |
14.30 |
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| 550 nm |
13.20 |
14.50 |
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| 575 nm |
13.40 |
14.70 |
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| 600 nm |
13.50 |
14.80 |
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| 625 nm |
13.60 |
14.90 |
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| 650 nm |
13.70 |
15.00 |
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| 675 nm |
13.80 |
15.00 |
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| 700 nm |
13.90 |
15.10 |
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Calculated Relative Intensity Colors of Alacranite in Air
Relative
Intensity |
0% |
70% |
100% |
140% |
210% |
280% |
350% |
420% |
490% |
560% |
630% |
670% |
| R1 |
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| R2 |
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Calculated Properties of Alacranite
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| Electron Density: |
Bulk Density (Electron Density)=3.16 gm/cc
note: Specific Gravity of Alacranite =3.44 gm/cc.
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| Fermion Index: |
Fermion Index = 0.0024375405
Boson Index = 0.9975624595 |
| Photoelectric: |
PEAlacranite = 49.28 barns/electron
U=PEAlacranite x rElectron Density= 155.79 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Alacranite is Not Radioactive |
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Alacranite Classification
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| Dana Class: |
02.08.22.04 (02)Sulfides - Including Selenides and Tellurides |
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(02.08)where Am Bn Xp, with (m+n):p=1:1 |
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(02.08.22)Realgar Series |
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02.08.22.01 Realgar AsS P 21/n 2/m |
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02.08.22.02 Pararealgar AsS P 21/c 2/m |
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02.08.22.03 Uzonite As4S5 P 21/m 2/m |
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02.08.22.04 Alacranite As8S9 P 2/c 2/m |
| Strunz Class: |
02.FA.20 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf |
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02.F - Sulfides of Arsenic, Alkalies; Sulfides with Halide, Oxide, Hydroxide, H2O |
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02.FA -With As, (Sb), S |
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02.FA.20 Alacranite As8S9 P 2/c 2/m |
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Other Alacranite Information
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| References: |
NAME( AntBidBlaNic1) PHYS. PROP.(Am.Min.,v.73, p189, v 87, p 357, v 88, p 1796) OPTIC PROP.(Am.Min.,Vol.73,p189,1988, AntBidBlaNic1) |
| See Also: |
Links to other databases for Alacranite :
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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Alacranite
As8S9
Dana No: 02.08.22.04 Strunz No: 02.FA.20
Locality:
Notes:
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