Eskebornite Mineral Data

General Eskebornite Information

Chemical Formula:

CuFeSe2

Composition:

Molecular Weight = 277.31 gm

Iron 20.14 % Fe

Copper 22.91 % Cu

Selenium 56.95 % Se

______

100.00 %

Empirical Formula:

CuFe²⁺Se₂

Environment:

In low-temperature hydrothermal vein deposits.

IMA Status:

Valid Species (Pre-IMA) 1949

Locality:

From Eskeborn adit, Tilkerode, Harz Mountains, Germany. Link to MinDat.org Location Data.

Name Origin:

For the Eskeborn adit, Tilkerode, Germany, where first discovered.

Name Pronunciation:

Eskebornite + Pronunciation

Synonym:

ICSD 73376

PDF 41-1464

Eskebornite Image

Images:

Eskebornite Jolliffeite

Comments: Back-scattered electron image of jolliffeite in sulfurian eskebornite. Note the cracked appearance and the different brightness of eskebornite, which is a reflection of variable ratio of selenium to sulfur. (CanMin v 42, p 844).
Location: Niederschlema-Alberoda uranium deposit, in the Erzgebirge region of Germany. Scale: See Image.
© Canadian Mineralogist

Eskebornite Crystallography

Axial Ratios:

a:c = 1:2.00217

Cell Dimensions:

a = 5.518, c = 11.048, Z = 2; V = 336.39 Den(Calc)= 2.74

Crystal System:

Tetragonal - ScalenohedralH-M Symbol (4 2m) Space Group: I 42d

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

By Intensity(I/I_o): 1.96(1), 3.19(0.95), 1.671(0.8),

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

Delgado J M , Diaz de Delgado G , Quintero M , Woolley J C , Materials Research Bulletin , 27 (1992) p.367-373, The crystal structure of copper iron selenide, CuFeSe2, Locality: synthetic

Physical Properties of Eskebornite

Cleavage:

{001} Perfect

Color:

Bronze.

Density:

5.35

Diaphaneity:

Opaque

Habit:

Inclusions - Generally found as inclusions in other minerals.

Habit:

Pseudo Cubic - Crystals show a cubic outline.

Hardness:

3-3.5 - Calcite-Copper Penny

Luster:

Metallic

Magnetism:

Distinctly magnetic

Streak:

black

Optical Properties of Eskebornite

RL Anisotrophism:

Marked, yellowish to tan.

RL Color:

Brown-yellow or cream-yellow, sometimes with an orange tint.

RL Pleochroism:

Creamy yellow to yellowish brown.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Eskebornite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	23.50	28.00
420 nm	24.50	29.00
440 nm	25.50	30.00
460 nm	26.40	31.10
480 nm	27.20	32.20
500 nm	28.00	33.40
520 nm	28.70	34.40
540 nm	29.40	35.00
560 nm	30.00	35.30
580 nm	30.60	35.50
600 nm	31.00	35.80
620 nm	31.50	36.00
640 nm	31.90	36.40
660 nm	32.20	37.00
680 nm	32.60	37.70
700 nm	33.00	38.70

**Calculated Relative Intensity Colors of Eskebornite in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%	340%
R₁
R₂

Calculated Properties of Eskebornite

Electron Density:

Bulk Density (Electron Density)=2.43 gm/cc
note: Specific Gravity of Eskebornite =2.74 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Eskebornite= 62.47 barns/electron
U=PE_Eskebornite x rElectron Density= 151.84 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Eskebornite is Not Radioactive

Eskebornite Classification

Dana Class:

02.09.01.02 (02)Sulfides - Including Selenides and Tellurides

(02.09)where Am Bn Xp, with (m+n):p=1:1

(02.09.01)Chalcopyrite Group (Tetragonal: I-42d)

02.09.01.01 Chalcopyrite CuFeS2 I 42d 4 2m

02.09.01.02 Eskebornite CuFeSe2 I 42d 4 2m

02.09.01.03 Gallite CuGaS2 I 42d 4 2m

02.09.01.04 Roquesite CuInS2 I 42d 4 2m

02.09.01.05 Lenaite AgFeS2 P 4₂mc 4mm

02.09.01.06 Laforetite! AgInS2 I 42d 4 2m

Strunz Class:

02.CB.10a 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.C - Metal Sulfides, M:S = 1:1 (and similar)

02.CB -With Zn, Fe, Cu, Ag, Au, etc

02.CB.10a Chalcopyrite CuFeS2 I 42d 4 2m

02.CB.10a Eskebornite CuFeSe2 I 42d 4 2m

02.CB.10a Gallite CuGaS2 I 42d 4 2m

02.CB.10a Laforetite! AgInS2 I 42d 4 2m

02.CB.10a Lenaite AgFeS2 P 4₂mc 4mm

02.CB.10a Roquesite CuInS2 I 42d 4 2m

Other Eskebornite Information

References:

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

See Also:

Links to other databases for Eskebornite :
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
15 - WWW-MINCRYST

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Print or Cut-and-Paste your Eskebornite Specimen Label here :

Eskebornite

CuFeSe2
Dana No: 02.09.01.02 Strunz No: 02.CB.10a
Locality:

Notes: