Empressite Mineral Data

Empressite Mineral Data +

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General Empressite Information

Chemical Formula:

AgTe

Composition:

Molecular Weight = 235.27 gm

Silver 46.31 % Ag

Tellurium 53.69 % Te

______

100.00 %

Empirical Formula:

Ag_1.01Te_0.99

Environment:

Low temperature gold-poor hydrothermal vein deposits.

IMA Status:

Valid Species (Pre-IMA) 1914

Locality:

Empress Josephine mine, Saguache County and Red Cloud mine, Bolder County, Colorado, USA. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Empressite Image

Images:

Empressite Tellurium

Comments: Bronze-colored microcrystals of empressite with bright native tellurium crystals.
Location: Rex mine, Boulder County, Colorado, USA. Scale: 1.9 x 1.4 x 0.7 cm.
© Richard Dale / Dale Minerals

Empressite Crystallography

Axial Ratios:

a:b:c =0.4418:1:0.2295

Cell Dimensions:

a = 8.882, b = 20.1, c = 4.614, Z = 16; V = 823.73 Den(Calc)= 7.59

Crystal System:

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

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

By Intensity(I/I_o): 2.699(1)(241), 2.2205(0.34)(400), 3.3277(0.3)(240),3.1742(0.26)(141), 2.3138(0.23)(261), 3.8(0.21)(031), 2.1371(0.2)(271), 2.8873(0.15)(231), 4.012(0.15)(111),

Crystal Structure:

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Bindi L , Spry P G , Cipriani C , American Mineralogist , 89 (2004) p.1043-1047, Empressite, AgTe, from the Empress-Josephine Mine, Colorado, USA:, Composition, physical properties, and determination of the crystal structure

Physical Properties of Empressite

Cleavage:

None

Color:

Bronze, Light bronze.

Density:

7.5 - 7.6, Average = 7.55

Diaphaniety:

Opaque

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Compact - Occurs as a compact mass.

Hardness:

3.5 - Copper Penny

Luster:

Metallic

Streak:

grayish black

Optical Properties of Empressite

RL Anisotrophism:

Strong, gray to yellowish white to grayish blue.

RL Bireflectance:

Moderate to strong.

RL Color:

Grayish white with no internal reflections.

RL Pleochroism:

Very strong, in gray to creamy white.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Empressite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	40.10	45.80
550 nm	39.60	44.10
589 nm	39.40	43.20
650 nm	38.90	41.80

**Calculated Relative Intensity Colors of Empressite in Air**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	230%
R₁
R₂

Calculated Properties of Empressite

Electron Density:

r_electron=6.38 gm/cc
note: r_Empressite=7.59 gm/cc.

Fermion Index

Fermion Index = 0.0429
Boson Index = 0.9571

Photoelectric:

PE_Empressite= 321.24 barns/electron
U=PE_Empressite x r_electron=2,050.92 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Empressite is Not Radioactive

Empressite Classification

Dana Class:

2.8.24.1 (2)Sulfides - Including Selenides and Tellurides

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

(2.8.24)Dana Group

2.8.24.1 Empressite AgTe Pmnb 2/m 2/m 2/m

Strunz Class:

II/B.05-90 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.05 - Achantite - Empresite series

II/B.05-02 Argentite* Ag2S I m3m 4/m 3 2/m

II/B.05-10 Acanthite Ag2S P 2₁/n 2/m

II/B.05-30 Naumannite Ag2Se P 2₁2₁2₁ 2 2 2

II/B.05-35 Kurilite* (Ag,Au)2(Te,Se,S) P m3n,P 4₃n Cubic

II/B.05-40 Hessite Ag2Te P 2₁/c 2/m

II/B.05-50 Aguilarite Ag4SeS P 2₁2₁2₁ 2 2 2

II/B.05-60 Cervelleite Ag4TeS Unk Cubic

II/B.05-70 Benleonardite Ag8(Sb,As)Te2S3 Tetra Tetra

II/B.05-75 Tsnigriite Ag9SbTe3(S,Se)3 P 2/m,Pm Mono

II/B.05-80 Stutzite Ag5-xTe3,(x=0.24-0.36) P 6/mmm 6/m 2/m 2/m

II/B.05-90 Empressite AgTe Pmnb 2/m 2/m 2/m

Other Empressite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8, AmMin, v 89, p 1043) OPTIC PROP.(AmMin, v 89, p 1044)

See Also:

Links to other databases for Empressite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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

Empressite

AgTe
Dana No: 2.8.24.1 Strunz No: II/B.05-90
Locality:

Notes: