Mineralogy Database

Chalcocite Mineral Data

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General Chalcocite Information

Help on Chemical  Formula: Chemical Formula: Cu2S
Help on Composition: Composition: Molecular Weight = 159.16 gm
   Copper  79.85 %  Cu
   Sulfur  20.15 %  S
          100.00 % 
Help on Empirical Formula: Empirical Formula: Cu2S
Help on Environment: Environment: Secondary mineral in or near the oxidized zone of copper sulfide deposits.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1832
Help on Locality: Locality: Cornwall, England and Butte, Montana. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek, meaning chalkos, "copper".
Help on Name Pronunciation: Name Pronunciation: Chalcocite + Pronunciation Say CHALCOCITE
Help on Synonym: Synonym: Cocinerite - mixture with silver

Chalcocite Image

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Comments: Chalcocite crystals in this specimen vary in size up to 1.2 cm across.
Location: Bristol nr. Hartford, Connecticut, USA. Scale: 7.6 x 4 cm.
© John Veevaert

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  Eskolaite   Chalcocite

Comments: Green crystalline eskolaite on massive chalcocite.
Location: Lubelin, Poland. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Chalcocite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.4348:1:0.4937
Help on Cell Dimensions: Cell Dimensions: a = 11.881, b = 27.323, c = 13.491, Z = 96; beta = 116.35° V = 3,924.48 Den(Calc)= 6.46
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/c
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 1.88(1), 1.9746(0.7), 2.403(0.7),
Help on Forms: Forms:

Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

Forms: ( 0 1 0) ( 0 1 2) ( 1 1 3) ( 1 1 0) ( 0 0 1)

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Physical Properties of Chalcocite

Help on Cleavage: Cleavage: {110} Indistinct
Help on Color: Color: Blue black, Gray, Black, Black gray, Steel gray.
Help on Density: Density: 5.5 - 5.8, Average = 5.65
Help on Diaphaneity: Diaphaneity: Opaque
Help on Fracture: Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Help on Habit: Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form.
Help on Habit: Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Hardness: Hardness: 2.5-3 - Finger Nail-Calcite
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Metallic
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: grayish black

Optical Properties of Chalcocite

Help on RL Anisotrophism: RL Anisotrophism: Weak.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Chalcocite in Air
λ R  ∑ R(λ) 
 400 nm   37.40   
 420 nm   36.70 
 440 nm   36.00 
 460 nm   35.20 
 480 nm   34.40 
 500 nm   33.50 
 520 nm   32.60 
 540 nm   31.80 
 560 nm   31.00 
 580 nm   30.20 
 600 nm   29.60 
 620 nm   29.00 
 640 nm   28.40 
 660 nm   28.00 
 680 nm   27.20 
 700 nm   27.10 
Calculated Relative Intensity Colors of Chalcocite in Air
   0%   40%   80% 100% 120% 160% 200% 240% 280% 300%

Calculated Properties of Chalcocite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=6.01 gm/cc
note: Specific Gravity of Chalcocite =6.46 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0015110456
Boson Index = 0.9984889544
Help on Photoelectric: Photoelectric: PEChalcocite = 37.21 barns/electron
U=PEChalcocite x rElectron Density= 223.51 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Chalcocite is Not Radioactive

Chalcocite 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
  (02.04.07)Chalcocite Group ([Cu]2-x S] formulae) Chalcocite Cu2S P 21/c 2/m Djurleite Cu31S16 P 21/n 2/m Digenite Cu9S5 R 3m 3 2/m Roxbyite Cu1.78S C 2/m 2/m Anilite Cu7S4 P nma 2/m 2/m 2/m Geerite Cu8S5 R 3m, R 3m, or R 32 Trig Spionkopite Cu1.4S P 3m1 ? 3m
Help on  Strunz Class: Strunz Class: 02.BA.05a 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.05a Chalcocite Cu2S P 21/c 2/m

Other Chalcocite Information

Help on References: References: NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
Help on See Also: See Also: Links to other databases for Chalcocite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - Franklin Minerals(Dunn)
5 - Franklin Minerals(Palache)
6 - GeoScienceWorld
7 - Glendale Community College
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - HyperPhysics
13 - MinDAT
14 - Mineral and Gemstone Kingdom
15 - Mineralienatlas (Deutsch)
16 - Online Mineral Museum
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - Scandinavian mineral gallery

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Dana No: Strunz No: 02.BA.05a





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