Chalcocite Mineral Data
General Chalcocite Information
Chemical Formula:
Cu2S
Composition:
Molecular Weight = 159.16 gm
Copper 79.85 % Cu
Sulfur 20.15 % S
______
100.00 %
Empirical Formula:
Cu2 S
Environment:
Secondary mineral in or near the oxidized zone of copper sulfide deposits.
IMA Status:
Valid Species (Pre-IMA) 1832
Locality:
Cornwall, England and Butte, Montana. Link to MinDat.org Location Data.
Name Origin:
From the Greek, meaning chalkos, "copper".
Name Pronunciation:
Chalcocite + Pronunciation
Synonym:
Cocinerite - mixture with silver
Chalcocite Image
Images:
Chalcocite
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
Images:
Chalcocite Crystallography
Axial Ratios:
a:b:c =0.4348:1:0.4937
Cell Dimensions:
a = 11.881, b = 27.323, c = 13.491, Z = 96; beta = 116.35° V = 3,924.48 Den(Calc)= 6.46
Crystal System:
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21 /c
X Ray Diffraction:
By Intensity(I/Io ): 1.88(1), 1.9746(0.7), 2.403(0.7),
Forms:
Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize
Keyboard
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)
Warning: this java applet does not work in some browsers because of security restrictions.
Physical Properties of Chalcocite
Cleavage:
{110} Indistinct
Color:
Blue black, Gray, Black, Black gray, Steel gray.
Density:
5.5 - 5.8, Average = 5.65
Diaphaneity:
Opaque
Fracture:
Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Habit:
Euhedral Crystals - Occurs as well-formed crystals showing good external form.
Habit:
Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Habit:
Massive - Uniformly indistinguishable crystals forming large masses.
Hardness:
2.5-3 - Finger Nail-Calcite
Luminescence:
Non-fluorescent.
Luster:
Metallic
Magnetism:
Nonmagnetic
Streak:
grayish black
Optical Properties of Chalcocite
RL Anisotrophism:
Weak.
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
Relative Intensity
0%
40%
80%
100%
120%
160%
200%
240%
280%
300%
R
Calculated Properties of Chalcocite
Electron Density:
Bulk Density (Electron Density)=6.01 gm/cc note: Specific Gravity of Chalcocite =6.46 gm/cc.
Fermion Index:
Fermion Index = 0.0015110456 Boson Index = 0.9984889544
Photoelectric:
PEChalcocite = 37.21 barns/electronU=PEChalcocite x r Electron Density= 223.51 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Chalcocite is Not Radioactive
Chalcocite Classification
Dana Class:
02.04.07.01 (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)
02.04.07.01 Chalcocite Cu2S P 21 /c 2/m
02.04.07.02 Djurleite Cu31S16 P 21 /n 2/m
02.04.07.03 Digenite Cu9S5 R 3 m 3 2/m
02.04.07.04 Roxbyite Cu1.78S C 2/m 2/m
02.04.07.05 Anilite Cu7S4 P nma 2/m 2/m 2/m
02.04.07.06 Geerite Cu8S5 R 3 m, R 3m, or R 32 Trig
02.04.07.07 Spionkopite Cu1.4S P 3m1 ? 3m
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
References:
NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
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
20 - WWW-MINCRYST
Search for Chalcocite using:
[AOL ]
[Bing ]
[Dog Pile ]
[GeoScienceWorld ]
[HotBot ]
[Ixquick ]
[Lycos ]
[MAMMA ]
[Scirus ]
[Teoma ]
[WebCrawler ]
[Wikipedia ]
[YAHOO ]
Visit our Advertisers for Chalcocite :
Ask about Chalcocite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in
Espa�ol
Print or Cut-and-Paste your Chalcocite Specimen Label here :
Chalcocite
Cu2S
Dana No: 02.04.07.01 Strunz No: 02.BA.05a
Locality:
Notes:
Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.