Launayite
A valid IMA mineral species
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Louis de Launay
Formula:
Cu2Pb20(Sb,As)26S60
Originally assumed to be CuPb10(Sb,As)13S30.
Colour:
Lead-gray
Lustre:
Metallic
Hardness:
3½ - 4
Specific Gravity:
5.83 (Calculated)
Crystal System:
Monoclinic
Name:
Named by John L. Jambor in 1967 in honor of Louis Auguste Alphonse de Launay (19 July 1860, Paris, France - 30 June 1938, Paris, France) for his contributions to the origins of mineral deposits. De Launay was a professor at the School of Mines in Paris, a geologist, speleologist, writer, biographer, and poet.
The modular description of the launayite structure (determined only in 2025 by Topa et al.) reveals a very close relationship with the structure of rouxelite: the parent structures of both can be regarded as merotypes.
The launayite crystal under investigation is built from distinct modulated domains which can be derived from a common simplified parent structure with C2/m symmetry and b∼4 Å (4 Å being the approximate edge length of an MS6 octahedron in sulfosalt structures). The model of this simplified structure was generated by halving the b axis, increasing the symmetry, merging duplicate atoms, removing minor positions, and moving the atoms onto the reflection planes at y=0 and y=1/2, respectively. Henceforth basis vectors and hkl indices will be given with respect to this parent structure.
The launayite crystal under investigation is built from distinct modulated domains which can be derived from a common simplified parent structure with C2/m symmetry and b∼4 Å (4 Å being the approximate edge length of an MS6 octahedron in sulfosalt structures). The model of this simplified structure was generated by halving the b axis, increasing the symmetry, merging duplicate atoms, removing minor positions, and moving the atoms onto the reflection planes at y=0 and y=1/2, respectively. Henceforth basis vectors and hkl indices will be given with respect to this parent structure.
Unique Identifiers
Mindat ID:
2341
Long-form identifier:
mindat:1:1:2341:8
IMA Classification of Launayite
Approved
IMA Formula:
Cu1+Pb2+10(Sb3+,As3+)13S2-30
Approval year:
1966
First published:
1967
Approval history:
In the IMA List of Minerals the chemical formula of launayite is given as CuPb10(Sb,As)13S20. This is a typo for CuPb10(Sb,As)13S30. The latter formula is the correct one for evident stoichiometric reasons and is also given in the IMA-approved report on sulfosalts
IMA 4.2 Correct chemical formula for launayite
IMA 4.2 Correct chemical formula for launayite
Classification of Launayite
2.LB.30
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
L : Unclassified Sulfosalts
B : With essential Pb
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
L : Unclassified Sulfosalts
B : With essential Pb
3.6.6.1
3 : SULFOSALTS
6 : 2 < ø < 2.49
3 : SULFOSALTS
6 : 2 < ø < 2.49
5.6.11
5 : Sulphosalts - Sulpharsenites and Sulphobismuthites (those containing Sn, Ge,or V are in Section 6)
6 : Sulpharsenites etc. of Pb alone
5 : Sulphosalts - Sulpharsenites and Sulphobismuthites (those containing Sn, Ge,or V are in Section 6)
6 : Sulpharsenites etc. of Pb alone
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Lau | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Lau | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Launayite
Metallic
Transparency:
Opaque
Colour:
Lead-gray
Streak:
Black
Hardness:
3½ - 4 on Mohs scale
Hardness:
VHN50=171 - 197 kg/mm2 - Vickers
Cleavage:
Perfect
{100} and {001}
{100} and {001}
Fracture:
Fibrous
Density:
5.83 g/cm3 (Calculated)
Optical Data of Launayite
Anisotropism:
Strong
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 470nm | 42.6% | 38.6% |
| 546nm | 43.8% | 36.9% |
| 589nm | 42.7% | 36.2% |
| 650nm | 40.9% | 35.5% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 43.8%.
R1 shown in black, R2 shown in red
Pleochroism:
Strong
Comments:
White to gray
Chemistry of Launayite
Mindat Formula:
Cu2Pb20(Sb,As)26S60
Originally assumed to be CuPb10(Sb,As)13S30.
Originally assumed to be CuPb10(Sb,As)13S30.
Element Weights:
Common Impurities:
As
Crystallography of Launayite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/b
Setting:
P2/a
Cell Parameters:
a = 42.6466(16) Å, b = 8.0381(2) Å, c = 34.3957(10) Å
β = 64.684(2)°
β = 64.684(2)°
Ratio:
a:b:c = 5.306 : 1 : 4.279
Unit Cell V:
10,658.42 ų (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.45 Å | (100) |
| 4.17 Å | (80) |
| 2.92 Å | (80) |
| 2.010 Å | (70) |
| 3.40 Å | (60) |
| 2.836 Å | (50) |
| 3.97 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Launayite
General Appearance of Type Material:
Observed only in polished sections.
Place of Conservation of Type Material:
Canadian Geological Survey, Ottawa, Canada, 12176.
Canadian Museum of Nature, Ottawa, Canada.
Canadian Museum of Nature, Ottawa, Canada.
Geological Setting of Type Material:
Marble.
Associated Minerals at Type Locality:
Synonyms of Launayite
Other Language Names for Launayite
Related Minerals - Strunz-mindat Grouping
| 2.LB. | Ciriottiite | Cu(Cu,Ag)3Pb19(Sb,As)22(As2)S56 |
| 2.LB. | Hayyanite | Cu5Ag11Pb76Sb71As17(As2+)8S224 |
| 2.LB. | Wenqingite | Pb5(AsS3)2(Ge2S6) |
| 2.LB.05 | Miharaite | Cu4FePbBiS6 |
| 2.LB.30 | Ardaite | Pb19Sb13S35Cl7 |
| 2.LB.30 | Sorbyite | CuPb9(Sb,As)11S26 |
| 2.LB.30 | Playfairite | Pb16(Sb,As)19S44Cl |
| 2.LB.30 | Sterryite | Cu(Ag,Cu)3Pb19(Sb,As)22(As2)S56 |
| 2.LB.30 | Madocite | Pb19(Sb,As)16S43 |
| 2.LB.35 | Larosite | (Cu,Ag)21PbBiS13 |
| 2.LB.40 | Mazzettiite | Ag3HgPbSbTe5 |
| 2.LB.40 | Petrovicite | Cu3HgPbBiSe5 |
| 2.LB.45 | Crerarite | Pt2-x(Bi,Pb)11(S,Se)11 |
| 2.LB.50 | Quijarroite | Cu6HgPb2Bi4Se12 |
| 2.LB.55 | Znamenskyite | Pb4In2Bi4S13 |
Other Information
Notes:
1:1 HNO3 rapidly tarnishes launayite iridescent, then black.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Launayite
mindat.org URL:
https://www.mindat.org/min-2341.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Launayite
Reference List:
Jambor, John Leslie (1967) New lead sulfantimonides from Madoc, Ontario. Part 2 - mineral descriptions. The Canadian Mineralogist, 9 (2) 191-213
Breskovska, Vesselina V., Mozgova, Nadejda N., Bortnikov, Nicolay S., Gorshkov, Anatoly I., Tzepin, Anatoly I. (1981) New data on chlorine sulfosalts. Bulletin de Minéralogie, 104 (6) 757-762 doi:10.3406/bulmi.1981.7521
Moëlo, Yves, Makovicky, Emil, Mozgova, Nadejda N., Jambor, John L., Cook, Nigel, Pring, Allan, Paar, Werner, Nickel, Ernest H., Graeser, Stephan, Karup-Møller, Sven, Balic-unic, Tonči, Mumme, William G., Vurro, Filippo, Topa, Dan (2008) Sulfosalt systematics: a review. Report of the sulfosalt sub-committee of the IMA Commission on Ore Mineralogy. European Journal of Mineralogy, 20 (1) 7-62 doi:10.1127/0935-1221/2008/0020-1778
Bosi, F.; Hatert, F.; Pasero, M.; Mills, S. J. (2024) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 80. European Journal of Mineralogy, 36 (4). 599-604 doi:10.5194/ejm-36-599-2024
Topa, D.; Stoeger, B.; Keutsch, F. N.; Ilinca, G. (2025) The crystal structure of launayite from Taylor Pit, Madoc, Ontario, Canada: crystal chemistry, modulated superstructures, and parent modular structure compared with rouxelite. European Journal of Mineralogy, 37 (6). 971-994 doi:10.5194/ejm-37-971-2025
Localities for Launayite
Showing 5 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.
Australia | |
| Bodon (2018) +2 other references |
Canada (TL) | |
| Jambor (1967) +3 other references |
Indonesia | |
| Nur et al. (2012) +1 other reference |
Slovakia | |
| Adamus B. et all. +2 other references |
Spain | |
| Rewitzer et al. (2019) +1 other reference |
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