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Acanthite Mineral Data

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General Acanthite Information

Help on Chemical  Formula: Chemical Formula: Ag2S
Help on Composition: Composition: Molecular Weight = 247.80 gm
   Silver  87.06 %  Ag
   Sulfur  12.94 %  S
          100.00 % 
Help on Empirical Formula: Empirical Formula: Ag2S
Help on Environment: Environment: Low-temperature sulfide veins and in zones of secondary enrichment.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1855
Help on Locality: Locality: Freiberg, Schneeberg, Annaberg, Germany. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek, akanta, meaning "arrow." After the Latin, argentum, meaning "silver". Argentite is stable above 179 C. Acanthite is stable below 179 deg. C.
Help on Name Pronunciation: Name Pronunciation: Acanthite + Pronunciation Say ACANTHITE
Help on Synonym: Synonym: ICSD 30445
  PDF 14-72
  Silver Glance

Acanthite Image

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Comments: Pseudo cubic acanthite crystals on matrix.
Location: Rayas mine, Guanajuato, Mexico. Scale: Size Not Given.
© Lou Perloff / Photo Atlas of Minerals

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  Argentite   Acanthite

Comments: Dark metallic acanthite crystals up to 3 mm. Most of the crystals are a cubic habit, so the acanthite is pseudomorphing the original argentite.
Location: San Juan de Rayas Mine (Rayas Mine), Guanajuato, Mun. de Guanajuato, Guanajuato, Mexico. Scale: 18x12x12 mm.
© John Betts - Fine Minerals

Acanthite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.6101:1:1.1343
Help on Cell Dimensions: Cell Dimensions: a = 4.229, b = 6.931, c = 7.862, Z = 4; beta = 99.61° V = 227.21 Den(Calc)= 7.24
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/n
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.606(1), 2.44(0.8), 2.383(0.75),

Physical Properties of Acanthite

Help on Cleavage: Cleavage: {001} Poor, {110} Poor
Help on Color: Color: Lead gray, Gray, Iron black.
Help on Density: Density: 7.2 - 7.4, Average = 7.3
Help on Diaphaneity: Diaphaneity: Opaque
Help on Fracture: Fracture: Sectile - Curved shavings or scrapings produced by a knife blade, (e.g. graphite).
Help on Habit: Habit: Arborescent - "Tree like" growths of branched systems (e.g. silver).
Help on Habit: Habit: Blocky - Crystal shape tends to be equant (e.g. feldspars).
Help on Habit: Habit: Skeletal - Crystals form crude outlines with missing faces.
Help on Hardness: Hardness: 2-2.5 - Gypsum-Finger Nail
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Metallic
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: shining black

Optical Properties of Acanthite

Help on RL Anisotrophism: RL Anisotrophism: Weak.
Help on RL Bireflectance: RL Bireflectance: None.
Help on RL Pleochroism: RL Pleochroism: None.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Acanthite in Air
λ R  ∑ R(λ) 
 420 nm   32.90   
 440 nm   33.00 
 460 nm   33.10 
 480 nm   33.00 
 500 nm   32.70 
 520 nm   32.00 
 540 nm   31.20 
 560 nm   30.50 
 580 nm   29.90 
 600 nm   29.20 
 620 nm   28.70 
 640 nm   28.20 
 660 nm   27.60 
 680 nm   27.00 
 700 nm   26.40 
Calculated Relative Intensity Colors of Acanthite in Air
   0%   40%   80% 100% 120% 160% 200% 240% 280% 310%

Calculated Properties of Acanthite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=6.43 gm/cc
note: Specific Gravity of Acanthite =7.24 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0009705112
Boson Index = 0.9990294888
Help on Photoelectric: Photoelectric: PEAcanthite = 224.26 barns/electron
U=PEAcanthite x rElectron Density=1,441.48 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Acanthite is Not Radioactive

Acanthite Classification

Help on  Dana Class: Dana Class: (02)Sulfides - Including Selenides and Tellurides
  (02.04)where Am Bn Xp, with (m+n):p=2:1
  (02.04.01)Acanthite Group Acanthite Ag2S P 21/n 2/m Naumannite Ag2Se P 212121 2 2 2 Aguilarite Ag4SeS P 212121 2 2 2
Help on  Strunz Class: Strunz Class: 02.BA.30a 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
  02.B - Metal Sulfides, M:S > 1:1 (mainly 2:1)
  02.BA -With Cu, Ag, Au
02.BA.30a Acanthite Ag2S P 21/n 2/m
02.BA.30a Argentite* Ag2S I m3m 4/m 3 2/m

Other Acanthite Information

Help on References: References: NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
Help on See Also: See Also: Links to other databases for Acanthite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - GeoScienceWorld
9 - Glendale Community College
10 - Google Images
11 - Google Scholar
12 - Handbook of Mineralogy (MinSocAm)
13 - Handbook of Mineralogy (UofA)
14 - HyperPhysics
15 - MinDAT
16 - Mineral and Gemstone Kingdom
17 - Mineralienatlas (Deutsch)
18 - Online Mineral Museum
19 - QUT Mineral Atlas
20 - Ruff.Info

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Dana No: Strunz No: 02.BA.30a





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