Mineralogy Database

Alacranite Mineral Data

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General Alacranite Information

Help on Chemical  Formula: Chemical Formula: As8S9
Help on Composition: Composition: Molecular Weight = 887.97 gm
   Arsenic  67.50 %  As
   Sulfur   32.50 %  S
           100.00 % 
Help on Empirical Formula: Empirical Formula: As8S9
Help on Environment: Environment: Occurs as a cement in a sandy gravel (Uson caldera, USSR); in hydrothermal As-S veins (Alacran deposit, Chile).
Help on IMA Status: IMA Status: Approved IMA 1986
Help on Locality: Locality: In the Uson caldera, Kamchatka, USSR. From the Alacran deposit, Pampa Larga, Chile. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: For the occurrence in the Alacran deposit, Chile.
Help on Name Pronunciation: Name Pronunciation: Alacranite + Pronunciation Say ALACRANITE
Help on Synonym: Synonym: ICSD 42387
  PDF 42-537

Alacranite Image

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Comments: Red crystals of alacranite.
Location: Mine Wilmsdorfer Schacht, Possendorf near Dresden, Sachsen, Germany. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Alacranite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.0355:1:0.9559
Help on Cell Dimensions: Cell Dimensions: a = 9.942, b = 9.601, c = 9.178, Z = 2; beta = 101.94° V = 857.12 Den(Calc)= 3.44
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2/c
Help on X Ray Diffraction: 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),

Physical Properties of Alacranite

Help on Cleavage: Cleavage: {???} Indistinct
Help on Color: Color: Red, Orange yellow.
Help on Density: Density: 3.4 - 3.46, Average = 3.43
Help on Diaphaneity: Diaphaneity: Transparent
Help on Habit: Habit: Equant Grains - Granular material with equel dimensions in x, y, and z.
Help on Habit: Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form.
Help on Hardness: Hardness: 1.5 - Between Talc and Gypsum
Help on Luster: Luster: Adamantine - Greasy
Help on Streak: Streak: orange

Optical Properties of Alacranite

Help on Optical Data: Optical Data: Biaxial (+), a=2.39, g=2.52, bire=0.1300
Help on Pleochroism (x): Pleochroism (x): orange yellow.
Help on Pleochroism (y): Pleochroism (y): orange yellow.
Help on Pleochroism (z): Pleochroism (z): orange yellow.
Help on RL Color: RL Color: Light gray with rose-yellow internal reflections.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Alacranite in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm   13.00   14.00 
 425 nm   13.20   14.60 
 450 nm   13.30   14.80 
 475 nm   13.40   14.80 
 500 nm   13.30   14.50 
 525 nm   13.10   14.30 
 550 nm   13.20   14.50 
 575 nm   13.40   14.70 
 600 nm   13.50   14.80 
 625 nm   13.60   14.90 
 650 nm   13.70   15.00 
 675 nm   13.80   15.00 
 700 nm   13.90   15.10 
Calculated Relative Intensity Colors of Alacranite in Air
   0%   70% 100% 140% 210% 280% 350% 420% 490% 560% 630% 670%

Calculated Properties of Alacranite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.16 gm/cc
note: Specific Gravity of Alacranite =3.44 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0024375405
Boson Index = 0.9975624595
Help on Photoelectric: Photoelectric: PEAlacranite = 49.28 barns/electron
U=PEAlacranite x rElectron Density= 155.79 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Alacranite is Not Radioactive

Alacranite Classification

Help on  Dana Class: Dana Class: (02)Sulfides - Including Selenides and Tellurides
  (02.08)where Am Bn Xp, with (m+n):p=1:1
  (02.08.22)Realgar Series Realgar AsS P 21/n 2/m Pararealgar AsS P 21/c 2/m Uzonite As4S5 P 21/m 2/m Alacranite As8S9 P 2/c 2/m
Help on  Strunz Class: Strunz Class: 02.FA.20 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
  02.F - Sulfides of Arsenic, Alkalies; Sulfides with Halide, Oxide, Hydroxide, H2O
  02.FA -With As, (Sb), S
02.FA.20 Alacranite As8S9 P 2/c 2/m

Other Alacranite Information

Help on References: 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)
Help on See Also: 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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Dana No: Strunz No: 02.FA.20





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