Lorandite Mineral Data

General Lorandite Information

Chemical Formula:

TlAsS2

Composition:

Molecular Weight = 343.44 gm

Thallium 59.51 % Tl

Arsenic 21.82 % As

Sulfur 18.67 % S

______

100.00 %

Empirical Formula:

TlAsS₂

Environment:

Low-temperature hydrothermal mineral.

IMA Status:

Valid Species (Pre-IMA) 1894

Locality:

Allchar, near Rozdan, northwest of Salonika, Macedonia. Link to MinDat.org Location Data.

Name Origin:

Named for Eotovos Laorand (1848-1919), physicist of Budapest, Hungary.

Name Pronunciation:

Lorandite + Pronunciation

Synonym:

ICSD 81094

PDF 19-1331

Lorandite Image

Images:

Lorandite Fangite

Comments: Brown crystals of fangite with red lorandite.
Location: Allchar, Roszdan, FYR Macedonia. Scale: Picture size 1.3 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Lorandite

Comments: Gemmy, transparent reddish brown crystals of lorandite on matrix.
Location: Allchar, near Majdan, Macedonia. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Lorandite Crystallography

Axial Ratios:

a:b:c =1.0837:1:0.5414

Cell Dimensions:

a = 12.29, b = 11.34, c = 6.14, Z = 8; beta = 104.6° V = 828.09 Den(Calc)= 5.51

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

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

By Intensity(I/I_o): 3.58(1), 3.59(0.6), 2.882(0.55),

Forms:

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Forms: ( 3 2 1) ( 0 1 1) ( 2 0 1) ( 2 0 1) ( 2 1 0) ( 1 1 0) ( 0 0 1)

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Crystal Structure:

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Zemann A , Zemann J , Acta Crystallographica , 12 (1959) p.1002-1006, Zur kenntnis der kristallstruktur von lorandit, TlAsS2

Physical Properties of Lorandite

Cleavage:

{100} Perfect, {001} Distinct

Color:

Red, Carmine red, Blackish lead gray.

Density:

5.5288 - 5.5362, Average = 5.53

Diaphaneity:

Subtransparent

Fracture:

Flexible - Flexible fragments.

Habit:

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

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

2-2.5 - Gypsum-Finger Nail

Luminescence:

Non-fluorescent.

Luster:

Sub Metallic

Magnetism:

Nonmagnetic

Streak:

red

Optical Properties of Lorandite

Optical Data:

Biaxial (+), a=2.72, 2V(Meas)=70-90. Dispersion r >> v strong.

Pleochroism (y):

purple-red.

Pleochroism (z):

orange-red.

RL Anisotrophism:

Strong.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Lorandite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	28.80	30.60
420 nm	28.70	30.70
440 nm	28.60	30.80
460 nm	28.40	30.90
480 nm	28.20	31.20
500 nm	27.80	31.10
520 nm	27.50	30.60
540 nm	27.00	29.80
560 nm	26.40	28.80
580 nm	25.80	27.70
600 nm	25.00	26.70
620 nm	24.40	26.00
640 nm	23.90	25.50
660 nm	23.50	25.00
680 nm	23.20	24.70
700 nm	22.90	24.50

**Calculated Relative Intensity Colors of Lorandite in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%	360%
R₁
R₂

Calculated Properties of Lorandite

Electron Density:

Bulk Density (Electron Density)=4.68 gm/cc
note: Specific Gravity of Lorandite =5.51 gm/cc.

Fermion Index:

Fermion Index = 0.0014005193
Boson Index = 0.9985994807

Photoelectric:

PE_Lorandite=1,047.21 barns/electron
U=PE_Lorandite x rElectron Density=4,905.95 barns/cc.

Radioactivity:

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

Lorandite Classification

Dana Class:

03.07.06.01 (03)Sulfides - Sulfosalts

(03.07)where z/y = 2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(03.07.06)Dana Group

03.07.06.01 Lorandite TlAsS2 P 2₁/a 2/m

Strunz Class:

02.HD.05 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.H - Sulfosalts of SnS Archetype

02.HD -With Tl

02.HD.05 Lorandite TlAsS2 P 2₁/a 2/m

02.HD.05 Weissbergite TlSbS2 P1 1

Other Lorandite Information

References:

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

See Also:

Links to other databases for Lorandite :
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 - Philatelic Mineralogy
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST

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

Lorandite

TlAsS2
Dana No: 03.07.06.01 Strunz No: 02.HD.05
Locality:

Notes: