Lorandite Mineral Data

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.

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

Diaphaniety:

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:

r_electron=4.68 gm/cc
note: r_Lorandite=5.51 gm/cc.

Fermion Index

Fermion Index = 0.0014
Boson Index = 0.9986

Photoelectric:

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

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Lorandite is Not Radioactive

Lorandite Classification

Dana Class:

3.7.6.1 (3)Sulfides - Sulfosalts

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

(3.7.6)Dana Group

3.7.6.1 Lorandite TlAsS2 P 2₁/a 2/m

Strunz Class:

II/E.13-50 II - Sulfides and sulphosalts

II/E - Sulfosalts (S : As,Sb,Bi = x) Sulfosalts with predominant Thallium and Mercury, x = 4.0 - 1.6

II/E.13 - Livingstonite - Vaughanite series

II/E.13-10 Livingstonite HgSb4S8 A2/a 2/m

II/E.13-20 Grumiplucite! HgBi2S4 C 2/m 2/m

II/E.13-30 Simonite TlHgAs3S6 P 2₁/n 2/m

II/E.13-40 Vrbaite Tl4Hg3Sb2As8S20 C mca 2/m 2/m 2/m

II/E.13-42 Edenharterite TlPbAs3S6 F dd2 mm2

II/E.13-43 Jentschite! TlPbAs2SbS6 P 2₁/n 2/m

II/E.13-45 Hutchinsonite (Pb,Tl)2As5S9 P bca 2/m 2/m 2/m

II/E.13-50 Lorandite TlAsS2 P 2₁/a 2/m

II/E.13-60 Weissbergite TlSbS2 P1 1

II/E.13-70 Tvalchrelidzeite Hg12(Sb,As)8S15 P1 1

II/E.13-80 Vaughanite TlHgSb4S7 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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 - Philatelic Mineralogy 12 -QUT Mineral Atlas 13 - WWW-MINCRYST 14 -École des Mines de Paris

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

Lorandite

TlAsS2
Dana No: 3.7.6.1 Strunz No: II/E.13-50
Locality:

Notes: