Lehmannite
A valid IMA mineral species
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About Lehmannite
Formula:
Na18Cu12TiO8(AsO4)8FCl5
Colour:
Dark greyish green to olive-greenish black
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
3.676 (Calculated)
Crystal System:
Monoclinic
Name:
Name in honour of Johann Gottlob Lehmann (4 August 1719, Langenhennersdorf, Electorate of Saxony – 22 January 1767, Saint Petersburg, Russian Empire) the outstanding German and Russian mineralogist and geologist, and one of the founders of stratigraphy.
Closely related to arsmirandite with which it was co-described.
The two have similar, unique structural features:
- Ti4+ (or Fe3+, in arsmirandite) in cubic coordination;
- packing of unusual, nanoscale (~1.5 nm across) clusters, of the {[MCu12O8](AsO4)8} composition; M = Ti4+ in lehmannite
Na and halogen atoms are between the nanoclusters.
See also Lehmannite (of Brooke).
Associates also include various arseantes and sulfates.
The two have similar, unique structural features:
- Ti4+ (or Fe3+, in arsmirandite) in cubic coordination;
- packing of unusual, nanoscale (~1.5 nm across) clusters, of the {[MCu12O8](AsO4)8} composition; M = Ti4+ in lehmannite
Na and halogen atoms are between the nanoclusters.
See also Lehmannite (of Brooke).
Associates also include various arseantes and sulfates.
Unique Identifiers
Mindat ID:
53217
Long-form identifier:
mindat:1:1:53217:0
GUID
(UUID V4):
(UUID V4):
42890061-bd41-44b1-abf3-04a4dce33568
IMA Classification of Lehmannite
Approved
IMA Formula:
Na18Cu12TiO8(AsO4)8FCl5
Approval year:
2018
First published:
2020
Classification of Lehmannite
8.BK.35
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
K : With medium-sized and large cations, (OH, etc.):RO4 = 2:1, 2.5:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
K : With medium-sized and large cations, (OH, etc.):RO4 = 2:1, 2.5:1
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 |
---|---|---|
Leh | 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 Lehmannite
Vitreous
Transparency:
Translucent, Opaque
Comment:
"Strong vitreous"
Colour:
Dark greyish green to olive-greenish black
Comment:
Translucent only in thin sections.
Streak:
Greyish green with an olive hue.
Hardness:
4½ on Mohs scale
Hardness:
VHN100=339 - 537 kg/mm2 - Vickers
Comment:
Mohs estimated from VHN.
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
None observed.
Fracture:
Irregular/Uneven
Density:
3.676 g/cm3 (Calculated)
Optical Data of Lehmannite
Anisotropism:
Very weak.
Bireflectance:
Very weak.
Reflectivity:
Wavelength | R1 | R2 |
---|---|---|
400nm | 8.3% | 8.9% |
420nm | 8.2% | 8.9% |
440nm | 8.2% | 8.8% |
460nm | 8.1% | 8.7% |
470nm | 8.1% | 8.7% |
480nm | 8.1% | 8.7% |
500nm | 8.0% | 8.7% |
520nm | 8.0% | 8.6% |
540nm | 7.9% | 8.6% |
546nm | 7.9% | 8.5% |
560nm | 7.9% | 8.5% |
580nm | 7.8% | 8.5% |
589nm | 7.6% | 8.4% |
600nm | 7.7% | 8.4% |
620nm | 7.7% | 8.4% |
640nm | 7.6% | 8.3% |
650nm | 7.6% | 8.3% |
660nm | 7.6% | 8.3% |
680nm | 7.5% | 8.2% |
700nm | 7.5% | 8.1% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 8.9%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Dark grey.
Internal Reflections:
Weak, brown.
Pleochroism:
Not Visible
Chemistry of Lehmannite
Mindat Formula:
Na18Cu12TiO8(AsO4)8FCl5
Crystallography of Lehmannite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 10.824(1) Å, b = 21.108(2) Å, c = 11.856(1) Å
β = 117.195(8)°
β = 117.195(8)°
Ratio:
a:b:c = 0.513 : 1 : 0.562
Unit Cell V:
2409.2 ų
Morphology:
Individual crystals are equant, thick tabular or short prismatic, with pyramid-like terminations.
Twinning:
Cyclic interpenetration twins, similar to phillipsite.
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
10.52 Å | (65) |
8.74 Å | (100) |
5.419 Å | (36) |
5.273 Å | (74) |
3.722 Å | (37) |
2.636 Å | (43) |
2.573 Å | (98) |
1.889 Å | (33) |
Comments:
Arsenatnaya fumarole, Kamchatka Krai, Russia. Data from the type description.
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 7: Great Oxidation Event | <2.4 |
45a : [Sulfates, arsenates, selenates, antimonates] | |
45b : [Other oxidized fumarolic minerals] |
Geological Setting:
Volcanic fumarole
Type Occurrence of Lehmannite
General Appearance of Type Material:
Equant crystals, up to 20 × 20 × 30 sq. μm, usually intergrown to form thin crusts, up to 2 × 3 cm in area.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Leninskiy Prospekt 18-2, Moscow 119071, Russia, registration number 5065/1.
Geological Setting of Type Material:
Volcanic fumarole.
Associated Minerals at Type Locality:
Reference:
Pekov, I.V., Britvin, S.N., Yapaskurt, V.O., Koshlyakova, N.N., Polekhovsky, Yu.S., Göttlicher, J., Chukanov, N.V., Vigasina, M.F., Krivovichev, S.V., Turhkova, A.G., Sidorov, E.G. (2020) Arsmirandite, Na18Cu12Fe3+O8(AsO4)8Cl5, and lehmannite, Na18Cu12TiO8(AsO4)8FCl5, new minerals from fumerole exhalations of the Tolbachik Volcano, Kamchatka, Russia. Zapiski RMO: 149: 1-17.
Synonyms of Lehmannite
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
8.BK.05 | Brazilianite | NaAl3(PO4)2(OH)4 |
8.BK.10 | Medenbachite | Bi2Fe3+Cu2+(AsO4)2O(OH)3 |
8.BK.10 | Neustädtelite | Bi2Fe3+(Fe3+,Co)(AsO4)2(O,OH)4 |
8.BK.10 | Cobaltneustädtelite | Bi2Fe3+(Co,Fe3+)(AsO4)2(O,OH)4 |
8.BK.15 | Curetonite | Ba(Al,Ti)(PO4)(OH,O)F |
8.BK.20 | Heyite | Pb5Fe2+2(VO4)2O4 |
8.BK.25 | Jamesite | Pb2Zn(Fe2+,Zn)2Fe3+4(AsO4)4(OH)10 |
8.BK.25 | Lulzacite | Sr2Fe2+(Fe2+,Mg)2Al4(PO4)4(OH)10 |
8.BK.25 | Désorite | Pb2(Fe3+6Zn)O2(PO4)4(OH)8 |
8.BK.30 | Nishanbaevite | KAl2O(AsO4)(SO4) |
8.BK.35 | Arsmirandite | Na18Cu12Fe3+O8(AsO4)8Cl5 |
8.BK.35 | Lebedevite | K4Na14Cu14O8(AsO4)8Cl6 |
Other Information
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 Lehmannite
mindat.org URL:
https://www.mindat.org/min-53217.html
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References for Lehmannite
Localities for Lehmannite
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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Russia (TL) | |
| Pekov et al. (2020) |
Quick NavTopAbout LehmanniteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia