Eucairite Mineral Data

Eucairite Mineral Data +

General Eucairite Information

Chemical Formula:

CuAgSe

Composition:

Molecular Weight = 250.37 gm

Copper 25.38 % Cu

Silver 43.08 % Ag

Selenium 31.54 % Se

______

100.00 %

Empirical Formula:

CuAgSe

Environment:

Widely distributed in selenium deposits of hydrothermal origin; locally abundant with other selenides.

IMA Status:

Valid Species (Pre-IMA) 1818

Locality:

In Canada, in the Martin Lake mine near Lake Athabasca, Saskatchewan, and in the Kidd Creek mine, near Timmins, Ontario. Link to MinDat.org Location Data.

Name Origin:

From the Greek for "opportunity," because it was discovered shortly after discovery of the element selenium.

Eucairite Image

Images:

Eucairite

Comments: Black dendritic eucairite in white calcite crystal.
Location: Skrikerum Copper Mine, near Tyrsarum, Kalmar, Sweden. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Eucairite Schlemaite Clausthalite

Comments: Reflected-light digital-image of the intermixed schlemaite grain in type sample F2, from which the reflectance, crystallographic and crystal-structure data were obtained. (CanMin, v 41, p 1435).
Location: "Tiber" dike, -855-m level, block 5128, main shaft # 371, Niederschlema-Alberoda vein-type uranium depost at Hartensein, Erzgebirge, Germany. Scale: See Picture.
© Canadian Mineralogist

Images:

Eucairite Crookesite

Comments: Polished section (PPL) showing zoned crystal of cream-colored eucairite and pale lavender crookesite along with steel blue umangite and white clausthalite in dark gray gangue..
Location: Mine dump (tailings) of Shaft 371 near Hartenstein/Saxony, Germany. Scale: Picture size 5 mm.
© Thomas Schlothauer

Eucairite Crystallography

Axial Ratios:

a:b:c =1.0085:1:1.5503

Cell Dimensions:

a = 4.105, b = 4.07, c = 6.31, Z = 2; V = 105.42 Den(Calc)= 7.89

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pmmn

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

By Intensity(I/I_o): 2.494(1), 2.628(0.59), 2.89(0.5),

Crystal Structure:

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Frueh A J , Czamanske G K , Knight C , Zeitschrift fur Kristallographie , 108 (1957) p.389-396, The crystallography of eucairite, CuAgSe, Locality: Skrikerum, Sweden, Sample: orthorhombic subcell

View Additional jPOWD Structure files for Eucairite
[1]

Physical Properties of Eucairite

Cleavage:

None

Color:

Bronze, Bronze, Gray, Silver white, Tin white.

Density:

7.6 - 7.8, Average = 7.69

Diaphaniety:

Opaque

Fracture:

Brittle - Subconchoidal - Brittle frature with subconchoidal fragments

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Hardness:

2.5 - Finger Nail

Luster:

Metallic

Streak:

gray white

Optical Properties of Eucairite

RL Anisotrophism:

Strong.

RL Color:

Tin-white with a faint creamy tinge.

RL Pleochroism:

Weak.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Eucairite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	34.70	35.00
420 nm	34.80	35.10
440 nm	34.90	35.20
460 nm	35.30	35.50
480 nm	36.20	35.80
500 nm	37.00	36.40
520 nm	37.20	36.90
540 nm	37.10	37.20
560 nm	36.80	37.30
580 nm	36.30	37.00
600 nm	35.60	36.50
620 nm	35.00	35.70
640 nm	34.40	35.00
660 nm	33.80	34.40
680 nm	33.30	34.00
700 nm	32.90	33.80

**Calculated Relative Intensity Colors of Eucairite in Air**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	240%	260%
R₁
R₂

Calculated Properties of Eucairite

Electron Density:

r_electron=6.93 gm/cc
note: r_Eucairite=7.89 gm/cc.

Fermion Index

Fermion Index = 0.02396
Boson Index = 0.97604

Photoelectric:

PE_Eucairite= 149.06 barns/electron
U=PE_Eucairite x r_electron=1,033.38 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Eucairite is Not Radioactive

Eucairite Classification

Dana Class:

2.4.6.2 (2)Sulfides - Including Selenides and Tellurides

(2.4)where Am Bn Xp, with (m+n):p=2:1

(2.4.6)Dana Group

2.4.6.1 Stromeyerite AgCuS C mcm 2/m 2/m 2/m

2.4.6.2 Eucairite CuAgSe Pmmn 2/m 2/m 2/m

Strunz Class:

II/B.06-40 II - Sulfides and sulphosalts

II/B - Sulfides with metal: sulfur, selenium and tellurium > 1:1, Sulfides, Selenides and Tellurides with predominant Copper and Silver/Gold

II/B.06 - Jalpaite - Imiterite series

II/B.06-10 Jalpaite Ag3CuS2 I 4₁/amd 4/m 2/m 2/m

II/B.06-20 Mckinstryite (Ag,Cu)2S Pnam 2/m 2/m 2/m

II/B.06-30 Stromeyerite AgCuS C mcm 2/m 2/m 2/m

II/B.06-40 Eucairite CuAgSe Pmmn 2/m 2/m 2/m

II/B.06-50 Henryite Cu4Ag3Te4 Unk Cubic

II/B.06-55 Brodtkorbite! Cu2HgSe2 P 2₁/n 2/m

II/B.06-60 Imiterite Ag2HgS2 P 2₁/c 2/m

Other Eucairite Information

References:

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

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Eucairite

CuAgSe
Dana No: 2.4.6.2 Strunz No: II/B.06-40
Locality:

Notes: