Gabrielite Mineral Data

General Gabrielite Information

Chemical Formula:

Tl2AgCu2As3S7

Composition:

Molecular Weight = 1,082.85 gm

Thallium 37.37 % Tl

Copper 12.68 % Cu

Silver 8.47 % Ag

Antimony 1.80 % Sb

Arsenic 18.96 % As

Sulfur 20.73 % S

______

100.00 %

Empirical Formula:

Tl_1.98Ag_0.85Cu_2.16As_2.74Sb_0.16S₇

Environment:

Found in association with numerous other As sulfosalts. Related to imhofite; structure determined

IMA Status:

Approved IMA 2002 (Dana # Added)

Locality:

Lengenbach quarry, Binntal, Valais, Switzerland. Link to MinDat.org Location Data.

Name Origin:

Nameed for Walter Gabriel (b. 1943), of Basel, Switzerland, a well-known mineral photographer and expert on Lengenbach minerals.

Synonym:

IMA2002-053

Gabrielite Image

Images:

Gabrielite

Comments: SEM picture of gabrielite showing the dominant (001) face with striation along a axis and (presumable) twinning along (100). (CanMin, v44:135).
Location: Lengenbach locality, at Binntal, Canton Valais, Switzerland. Scale: See Image.
© Canadian Mineralogist

Gabrielite Crystallography

Axial Ratios:

a:b:c =0.9952:1:1.3073

Cell Dimensions:

a = 12.138, b = 12.196, c = 15.944, Z = 6; alpha = 78.537°, beta = 84.715°, gamma = 60.47° V = 2,004.15 Den(Calc)= 5.38

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 15.631(1)(001 ), 3.143(0.9)(214), 3.531(0.8)(300 ), 2.911(0.7)(422 ), 2.52(0.6)(223), 2.978(0.6)(324 ), 3.263(0.5)(031), 3.468(0.4)(233 ), 3.944(0.4)(32

Crystal Structure:

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Balic-Zunic T , Makovicky E , Karanovic L , Poleti D , Graeser S , The Canadian Mineralogist , 44 (2006) p.141-158, The crystal structure of gabrielite, Tl2AgCu2As3S7, a new species, of thallium sulfosalt from Lengenbach, Switzerland, Locality: Lengenbach, Switzerland

Physical Properties of Gabrielite

Cleavage:

{001} Very Good

Color:

Black.

Diaphaneity:

Opaque

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Pseudo Hexagonal - Crystals show a hexagonal outline.

Habit:

Striated - Parallel lines on crystal surface or cleavage face.

Hardness:

1.5-2 - Talc-Gypsum

Luster:

Metallic

Streak:

blackish red

Optical Properties of Gabrielite

RL Anisotrophism:

Weak.

RL Bireflectance:

None.

RL Color:

White with red internal reflections.

RL Pleochroism:

None.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Gabrielite in Air**
λ	R	∑ R(λ)
460 nm	30.70
470 nm	30.53
540 nm	29.40
546 nm	29.10
580 nm	28.20
589 nm	27.94
640 nm	26.80
650 nm	26.35

**Calculated Relative Intensity Colors of Gabrielite in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%
R

Calculated Properties of Gabrielite

Electron Density:

Bulk Density (Electron Density)=4.69 gm/cc
note: Specific Gravity of Gabrielite =5.36 gm/cc.

Fermion Index:

Fermion Index = 0.0015546564
Boson Index = 0.9984453436

Photoelectric:

PE_Gabrielite= 677.90 barns/electron
U=PE_Gabrielite x rElectron Density=3,178.01 barns/cc.

Radioactivity:

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

Gabrielite Classification

Dana Class:

03.05.11.02 (03)Sulfides - Sulfosalts

(03.05)where 2.5 < z/y < 3 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(03.05.11)Dana Group

03.05.11.01 Imhofite Tl6CuAs16S40 P 2₁/n 2/m

03.05.11.02 Gabrielite! Tl2AgCu2As3S7 P1 1

Strunz Class:

02.HD.60 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.H - Sulfosalts of SnS Archetype

02.HD -With Tl

02.HD.60 Gabrielite! Tl2AgCu2As3S7 P1 1

Other Gabrielite Information

References:

NAME( AmMin, v91, p1946) PHYS. PROP.(AmMin, v91, p1946) OPTIC PROP.(AmMin, v91, p1946)

See Also:

Links to other databases for Gabrielite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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

Gabrielite

Tl2AgCu2As3S7
Dana No: 03.05.11.02 Strunz No: 02.HD.60
Locality:

Notes: