Freibergite Mineral Data

Freibergite Mineral Data +

General Freibergite Information

Chemical Formula:

(Ag,Cu,Fe)12(Sb,As)4S13

Composition:

Molecular Weight = 1,929.46 gm

Iron 3.47 % Fe

Copper 11.86 % Cu

Silver 40.25 % Ag

Antimony 18.93 % Sb

Arsenic 3.88 % As

Sulfur 21.60 % S

______

100.00 %

Empirical Formula:

Ag_7.2Cu_3.6Fe²⁺_1.2Sb₃AsS₁₃

Environment:

In hydrothermal deposits.

IMA Status:

Valid Species (Pre-IMA) 1853

Locality:

Freiberg district, Saxony. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Synonym:

ICSD 62116

PDF 27-190

Freibergite Image

Images:

Freibergite

Comments: Dark metallic freibergite in white quartz.
Location: Freiberg, Freiberg District, Erzgebirge, Saxony, Germany. Scale: 35x20x10 mm.
© John Betts - Fine Minerals

Freibergite Crystallography

Cell Dimensions:

a = 10.47, Z = 2; V = 1,147.73 Den(Calc)= 5.58

Crystal System:

Isometric - HextetrahedralH-M Symbol (4 3m) Space Group: I 43m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.05(1), 1.862(0.7), 2.64(0.5),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Peterson R C , Miller I , Mineralogical Magazine , 50 (1986) p.717-721, Crystal structure and cation distribution in freibergite and tetrahedrite, Locality: Keno Hill, Yukon, Canada

Physical Properties of Freibergite

Cleavage:

None

Color:

Gray, Steel gray, Black.

Density:

4.85 - 5, Average = 4.92

Diaphaniety:

Opaque

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Metallic

Streak:

reddish black

Optical Properties of Freibergite

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Freibergite in Air**
λ	R	∑ R(λ)
400 nm	35.20
420 nm	35.10
440 nm	35.00
460 nm	34.70
480 nm	34.30
500 nm	33.70
520 nm	33.10
540 nm	32.60
560 nm	32.20
580 nm	31.80
600 nm	31.40
620 nm	30.90
640 nm	30.50
660 nm	30.00
680 nm	29.50
700 nm	29.00

**Calculated Relative Intensity Colors of Freibergite in Air**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	240%	270%	290%
R

Calculated Properties of Freibergite

Electron Density:

r_electron=5.02 gm/cc
note: r_Freibergite=5.58 gm/cc.

Fermion Index

Fermion Index = 0.00235
Boson Index = 0.99765

Photoelectric:

PE_Freibergite= 174.53 barns/electron
U=PE_Freibergite x r_electron= 876.24 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Freibergite is Not Radioactive

Freibergite Classification

Dana Class:

3.3.6.3 (3)Sulfides - Sulfosalts

(3.3)where 3 < z/y < 4 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(3.3.6)Tetrahedrite Group (Isometric: I4¯3m)

3.3.6.1 Tetrahedrite (Cu,Fe)12Sb4S13 I 43m 4 3m

3.3.6.2 Tennantite (Cu,Fe)12As4S13 I 43m 4 3m

3.3.6.3 Freibergite (Ag,Cu,Fe)12(Sb,As)4S13 I 43m 4 3m

3.3.6.4 Hakite (Cu,Hg)3(Sb,As)(Se,S)3 I 43m 4 3m

3.3.6.5 Giraudite (Cu,Zn,Ag)12(As,Sb)4(Se,S)13 I 43m 4 3m

3.3.6.6 Goldfieldite Cu12(Te,Sb,As)4S13 I 43m 4 3m

3.3.6.7 Argentotennantite (Ag,Cu)10(Zn,Fe)2(As,Sb)4S13 I 43m 4 3m

Strunz Class:

II/C.11-50 II - Sulfides and sulphosalts

II/C - Sulfides with metal: sulfur, selenium and tellurium = 1:1

II/C.11 - Tetrahedrite group

II/C.11-10 Tennantite (Cu,Fe)12As4S13 I 43m 4 3m

II/C.11-20 Argentotennantite (Ag,Cu)10(Zn,Fe)2(As,Sb)4S13 I 43m 4 3m

II/C.11-30 Giraudite (Cu,Zn,Ag)12(As,Sb)4(Se,S)13 I 43m 4 3m

II/C.11-40 Tetrahedrite (Cu,Fe)12Sb4S13 I 43m 4 3m

II/C.11-50 Freibergite (Ag,Cu,Fe)12(Sb,As)4S13 I 43m 4 3m

II/C.11-60 Goldfieldite Cu12(Te,Sb,As)4S13 I 43m 4 3m

II/C.11-70 Hakite (Cu,Hg)3(Sb,As)(Se,S)3 I 43m 4 3m

II/C.11-75 Mgriite Cu3AsSe3 F d3m 4/m 3 2/m

II/C.11-80 Chameanite (Cu,Fe)4As(Se,S)4 I 43m 4 3m

Other Freibergite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

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Freibergite

(Ag,Cu,Fe)12(Sb,As)4S13
Dana No: 3.3.6.3 Strunz No: II/C.11-50
Locality:

Notes: