Lorándite
A valid IMA mineral species - grandfathered
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About Lorándite
Baron Loránd von Eötvös
Formula:
TlAsS2
Colour:
Cochineal- to carmine-red; often dark lead-gray on the surface and frequently coated by an ochre-yellow powder.
Lustre:
Adamantine, Metallic
Hardness:
2 - 2½
Specific Gravity:
5.53
Crystal System:
Monoclinic
Name:
Named in honor of Prof. Loránd Eötvös (27 July 1848, Buda, Kingdom of Hungary - 8 April 1919, Budapest, Hungarian Soviet Republic), physicist, mathematician and politician of Budapest. He studied gravity and the gravitational gradient on the Earth's surface. The gravitational gradient is important in applied geophysics for locating petroleum and mineral deposits. The CGS unit for gravitational gradient is named the eotvos in his honor. A crater on the Moon and an asteroid are also named after him.
Type Locality:
Chemically, the As analogue of (triclinic) weissbergite.
Some unique occurrences (China) are mined as thallium ore.
Some unique occurrences (China) are mined as thallium ore.
Name Encoding
ASCII-7:
Lorandite
Unique Identifiers
Mindat ID:
2434
Long-form identifier:
mindat:1:1:2434:7
IMA Classification of Lorándite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Tl1+As3+S2-2
First published:
1894
Classification of Lorándite
2.HD.05
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
D : With Tl
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
D : With Tl
3.7.6.1
3 : SULFOSALTS
7 : ø = 2
3 : SULFOSALTS
7 : ø = 2
5.5.1
5 : Sulphosalts - Sulpharsenites and Sulphobismuthites (those containing Sn, Ge,or V are in Section 6)
5 : Sulpharsenites etc. of Tl
5 : Sulphosalts - Sulpharsenites and Sulphobismuthites (those containing Sn, Ge,or V are in Section 6)
5 : Sulpharsenites etc. of Tl
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Lor | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Lorándite
Adamantine, Metallic
Transparency:
Transparent, Translucent
Colour:
Cochineal- to carmine-red; often dark lead-gray on the surface and frequently coated by an ochre-yellow powder.
Streak:
Cherry-red
Hardness:
2 - 2½ on Mohs scale
Tenacity:
Elastic
Cleavage:
Very Good
{100} excellent; {201} very good; {001} good.
{100} excellent; {201} very good; {001} good.
Density:
5.53 g/cm3 (Measured) 5.53 g/cm3 (Calculated)
Optical Data of Lorándite
Type:
Biaxial (+)
RI values:
nα = 2.72
Surface Relief:
Moderate
Anisotropism:
Strong
Dispersion:
relatively strong
Optical Extinction:
X, Y ≃ ⊥ {100}; Z = b.
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 400nm | 28.8% | 30.6% |
| 420nm | 28.7% | 30.7% |
| 440nm | 28.6% | 30.8% |
| 460nm | 28.4% | 30.9% |
| 480nm | 28.2% | 31.2% |
| 500nm | 27.8% | 31.1% |
| 520nm | 27.5% | 30.6% |
| 540nm | 27.0% | 29.8% |
| 560nm | 26.4% | 28.8% |
| 580nm | 25.8% | 27.7% |
| 600nm | 25.0% | 26.7% |
| 620nm | 24.4% | 26.0% |
| 640nm | 23.9% | 25.5% |
| 660nm | 23.5% | 25.0% |
| 680nm | 23.2% | 24.7% |
| 700nm | 22.9% | 24.5% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 31.2%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Bluish gray-white
Internal Reflections:
Exhibited
Pleochroism:
Weak
Comments:
Y = purple-red; Z = orange-red.
Chemistry of Lorándite
Mindat Formula:
TlAsS2
Element Weights:
Elements listed:
Crystallography of Lorándite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/a
Cell Parameters:
a = 12.28(1) Å, b = 11.30(1) Å, c = 6.101(6) Å
β = 104.6°
β = 104.6°
Ratio:
a:b:c = 1.087 : 1 : 0.54
Unit Cell V:
819.26 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Short prismatic {110} and striated [001]; also prismatic {201}, {201}; tabular {201}.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.59 Å | (100) |
| 2.88 Å | (80) |
| 2.97 Å | (70) |
| 1.867 Å | (50) |
| 1.484 Å | (50) |
| 5.28 Å | (40) |
| 2.64 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Geological Setting:
Low temperature hydrothermal
Type Occurrence of Lorándite
General Appearance of Type Material:
Individual crystals 5-10 mm in size. Both tabular and prismatic.
Place of Conservation of Type Material:
Hungarian Natural History Museum, Budapest, Hungary (holotype).
Geological Setting of Type Material:
Low temperature hydrothermal.
Associated Minerals at Type Locality:
Other Language Names for Lorándite
Common Associates
Associations Based on Photo Data:
| 45 photos of Lorándite associated with Realgar | As4S4 |
| 37 photos of Lorándite associated with Orpiment | As2S3 |
| 27 photos of Lorándite associated with Raguinite | TlFeS2 |
| 5 photos of Lorándite associated with Fangite | Tl3AsS4 |
| 4 photos of Lorándite associated with Picropharmacolite | Ca4Mg(AsO4)2(HAsO4)2 · 11H2O |
| 3 photos of Lorándite associated with Calcite | CaCO3 |
| 3 photos of Lorándite associated with Philrothite | TlAs3S5 |
| 2 photos of Lorándite associated with Dorallcharite | TlFe3+3(SO4)2(OH)6 |
| 1 photo of Lorándite associated with Cinnabar | HgS |
| 1 photo of Lorándite associated with Lafossaite | Tl(Cl,Br) |
Related Minerals - Strunz-mindat Grouping
| 2.HD. | Enneasartorite | Tl6Pb32As70S140 |
| 2.HD. | Shimenite | Tl5Sb21-yAsyS34 |
| 2.HD. | Dewitite | AgzTl10-x-zPb2xSb42-x-yAsyS68 |
| 2.HD. | Buynite | TlPb14As17S40 |
| 2.HD. | Vallouiseite | Ag3Tl21.5PbSb63As41.5S170 |
| 2.HD. | Giuşcăite | Ag2Tl4Pb4As20Sb2S40 |
| 2.HD. | Boscardinite | TlPb4(Sb7As2)S18 |
| 2.HD. | Gungerite | TlAs5Sb4S13 |
| 2.HD.05e | Dalnegroite | (Tl4Pb2)(As12Sb8)S34 |
| 2.HD.05 | Weissbergite | TlSbS2 |
| 2.HD.05e | Chabournéite | AgzTl8-x-zPb4+2xSb40-x-yAsyS68 with 0.00 < x < 0.40(9), 16.15(3)< y < 19.11(10), 0.04(4) < z < 0.11(6) |
| 2.HD.15 | Christite | TlHgAsS3 |
| 2.HD.15 | Markwelchite | TlPbSbS3 |
| 2.HD.15 | Richardsollyite | TlPbAsS3 |
| 2.HD.20 | Jankovićite | Tl5Sb9(As,Sb)4S22 |
| 2.HD.25 | Rebulite | Tl5Sb5As8S22 |
| 2.HD.30 | Imhofite | Tl5.8As15.4S26 |
| 2.HD.35 | Edenharterite | PbTlAs3S6 |
| 2.HD.40 | Jentschite | TlPbAs2SbS6 |
| 2.HD.45 | Protochabournéite | Tl4-xPb2+2xSb20-x-yAsyS34 with 0.02(2) <= x <= 0.34(2), 5.71(9) <= y <= 6.69(9) |
| 2.HD.45 | Hutchinsonite | TlPbAs5S9 |
| 2.HD.50 | Bernardite | TlAs5S8 |
| 2.HD.55 | Sicherite | TlAg2(As,Sb)3S6 |
| 2.HD.55 | Geuerite | Ag2Tl4Pb4As22S40 |
| 2.HD.60 | Gabrielite | Tl6Ag3Cu6(As,Sb)9S21 |
| 2.HD.65 | Tsygankoite | Mn8Tl8Hg2(Sb21Pb2Tl)S48 |
| 2.HD.70 | Drechslerite | Tl4(Sb4-xAsx)S8 (1 < x < 2) |
Other Information
Notes:
Melts easily, colors a flame emerald green, and volatilizes entirely. Heated in a small flask it melts and decomposes into thallium and arsenic sulfide and arsenic acid, which precipitate on the walls as black, orange, and white colored rings. Dissolves in nitric acid, with the formation of sulfur.
Health Risks:
Contains thallium and arsenic → very toxic (though not well soluble); always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest.
Internet Links for Lorándite
mindat.org URL:
https://www.mindat.org/min-2434.html
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References for Lorándite
Reference List:
Zemann, Anna, Zemann, J. (1958) Der Strukturtyp von Lorandit, TIAsS2. Die Naturwissenschaften, 45 (20). 488 doi:10.1007/bf00635553
Zemann, A., Zemann, J. (1959) Zur Kenntnis der Kristallstruktur von Lorandit, TlAsS2. Acta Crystallographica, 12 (12) 1002-1006 doi:10.1107/s0365110x59002833
Graeser, Stefan (1967) Ein Vorkommen von Lorandit (TlAsS2) in der Schweiz. Contributions to Mineralogy and Petrology, 16 (1) 45-50 doi:10.1007/bf00371607
Localities for Lorándite
Showing 20 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
China | |
| Zhou et al. (2005) +1 other reference |
| Chen (1989) +5 other references |
| Zhiwei Bao et al. (2004) | |
| Han et al. (2020) |
Germany | |
| undefined +2 other references |
Iran | |
| Asadi +3 other references |
North Macedonia (TL) | |
| Krenner (1894) +6 other references |
| Nuclear Instruments and Methods in ... +6 other references | |
| Boev et al. (2016) +1 other reference | |
| Boev et al. (2016) +1 other reference | |
Russia | |
| Pekov (1998) |
| Kasatkin et al. (2019) +3 other references |
Switzerland | |
| Graeser (1967) +2 other references |
USA | |
| Castor et al. (2004) |
| Radtke et al. (1974) +2 other references |
| Bowell et al. (1999) +2 other references |
| Mineral News: 19 (12) |
| Wilson et al. (1991) |
| - (2005) |
| Dana 7:I:293 +1 other reference |
Quick NavTopAbout LoránditeName EncodingUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Crven Dol, Allchar, Ržanovo, Kavadarci Municipality, North Macedonia