Lonsdaleite
A valid IMA mineral species
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Kathleen Lonsdale
Formula:
C
Colour:
Transparent brownish-yellow, grayish
Lustre:
Adamantine
Hardness:
7 - 8
Specific Gravity:
3.2
Crystal System:
Hexagonal
Name:
Named in honor of Dame Kathleen Lonsdale (nee Yardley) (28 January 1903, Newbridge, County Kildare, Ireland - 1 April 1971, London, England), crystallographer who established the structure of benzene by X-ray diffraction methods in 1929. She also worked on the synthesis of diamonds, and was a pioneer in the use of X-rays to study crystals.
Polymorph of:
Originally described as an allotrope of carbon based on a hexagonal lattice (Bundy & Kasper, 1967).
Németh et al. (2014) demonstrated "lonsdaleite" to be a faulted and twinned cubic diamond. He also showed that other reported carbon polymorphs can be explained by twinning and stacking faults.
On the other hand, both Kraus et al. (2016) and Turneaure et al. (2017) have proved lonsdaleite formation (alongside with diamond) - as a separate species - by shock compression of graphite. For further evidence see Tomkins et al. (2023).
Status in September 2023: almost certainly to be discredited, as a nanocomposite material (see Nèmeth et al.).
Németh et al. (2014) demonstrated "lonsdaleite" to be a faulted and twinned cubic diamond. He also showed that other reported carbon polymorphs can be explained by twinning and stacking faults.
On the other hand, both Kraus et al. (2016) and Turneaure et al. (2017) have proved lonsdaleite formation (alongside with diamond) - as a separate species - by shock compression of graphite. For further evidence see Tomkins et al. (2023).
Status in September 2023: almost certainly to be discredited, as a nanocomposite material (see Nèmeth et al.).
Unique Identifiers
Mindat ID:
2431
Long-form identifier:
mindat:1:1:2431:6
GUID
(UUID V4):
(UUID V4):
4c205d3f-fd47-4284-89db-039b69026f3d
IMA Classification of Lonsdaleite
Approved
First published:
1967
Type description reference:
Classification of Lonsdaleite
1.CB.10b
1 : ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)
C : Metalloids and Nonmetals
B : Carbon-silicon family
1 : ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)
C : Metalloids and Nonmetals
B : Carbon-silicon family
Dana 7th ed.:
1.3.5.3
1.3.6.3
1 : NATIVE ELEMENTS AND ALLOYS
3 : Semi-metals and non-metals
1 : NATIVE ELEMENTS AND ALLOYS
3 : Semi-metals and non-metals
1.27
1 : Elements and Alloys (including the arsenides, antimonides and bismuthides of Cu, Ag and Au)
1 : Elements and Alloys (including the arsenides, antimonides and bismuthides of Cu, Ag and Au)
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 |
|---|---|---|
| Lon | 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 Lonsdaleite
Adamantine
Transparency:
Transparent
Colour:
Transparent brownish-yellow, grayish
Hardness:
7 - 8 on Mohs scale
Hardness Data:
Measured
Comment:
Handbook of Mineralogy gives "3". "imperfections in natural Lonsdaleite reduce hardness, artificial material has tested harder than diamond (>10) , See Physical Review letters (2009). Wikipedia states “Lonsdaleite is simulated to be 58% harder than diamond on the <100> face and to resist indentation pressures of 152 GPa, whereas diamond would break at 97 GPa.[21] This is yet exceeded by IIa diamond's <111> tip hardness of 162 GPa.”
Density:
3.2 g/cm3 (Measured) 3.51 g/cm3 (Calculated)
Optical Data of Lonsdaleite
Type:
Uniaxial (+/-)
RI values:
nα = 2.404 nβ = 2.404
Birefringence:
slight
Max Birefringence:
δ = 2.404
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Very High
Chemistry of Lonsdaleite
Mindat Formula:
C
Elements listed:
Crystallography of Lonsdaleite
Crystal System:
Hexagonal
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
P63/mmc
Cell Parameters:
a = 2.51 Å, c = 4.12 Å
Ratio:
a:c = 1 : 1.641
Unit Cell V:
22.48 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Fine grained aggregates
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0012989 | Lonsdaleite | Bundy F P, Kasper J S (1967) Hexagonal diamond-a new form of carbon Journal of Chemical Physics 46 3437-3446 | 1967 | 0 | 293 | ||
| 0013990 | Lonsdaleite | Fayos J (1999) Possible 3D carbon structures as progressive intermediates in graphite to diamond phase transition Journal of Solid State Chemistry 148 278-285 | 1999 | 0 | 293 | ||
| 0018218 | Lonsdaleite | Yeh C, Lu Z, Froyen S, Zunger A (1992) Zinc-blende-Wurtzite polytypism in semiconductors _cod_database_code 1100004 Physical Review B46 10086-10097 | 1992 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.061 Å | (100) |
| 1.257 Å | (60) |
| 2.18 Å | (40) |
| 1.075 Å | (30) |
| 1.933 Å | (20) |
| 1.50 Å | (10) |
| 1.17 Å | (10) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
| Near-surface Processes | |
| 30 : Terrestrial impact minerals | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 36 : Carbonatites, kimberlites, and related igneous rocks |
Geological Setting:
In meteorites and kimberlite.
Type Occurrence of Lonsdaleite
General Appearance of Type Material:
Black cubes and cubo-octahedrons up to about 0.7 mm in size.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, 130245.
Geological Setting of Type Material:
Meteorite. Residue left from dissolving of the Canyon Diablo meteorite.
Associated Minerals at Type Locality:
Reference:
Frondel, C. & Marvin, U.B. (1967) Lonsdaleite, a new hexagonal polymorph of diamond. Nature: 214: 587-589.
Synonyms of Lonsdaleite
Other Language Names for Lonsdaleite
Common Associates
Related Minerals - Strunz-mindat Grouping
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 Lonsdaleite
mindat.org URL:
https://www.mindat.org/min-2431.html
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References for Lonsdaleite
Reference List:
Németh, Péter, Garvie, Laurence A. J. (2023) Questionable lonsdaleite identification in ureilite meteorites. Proceedings of the National Academy of Sciences, 120 (20) doi:10.1073/pnas.2304890120
Tomkins, Andrew G., Wilson, Nicholas C., MacRae, Colin, Salek, Alan, Field, Matthew, Brand, Helen E. A., Langendam, Andrew D., Stephen, Natasha R., Torpy, Aaron, Pintér, Zsanett, Jennings, Lauren A., McCulloch, Dougal (2023) Reply to Németh and Garvie: Evidence for lonsdaleite in ureilite meteorites. Proceedings of the National Academy of Sciences, 120 (20) doi:10.1073/pnas.2305559120
Németh, Péter, Garvie, Laurence A. J., Salzmann, Christoph G. (2023) Canyon Diablo lonsdaleite is a nanocomposite containing c/h stacking disordered diamond and diaphite. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 381 (2259) doi:10.1098/rsta.2022.0344
Localities for Lonsdaleite
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.
Antarctica | |
| Clarke Jr. +2 other references |
Australia | |
| Gennady P. Vdovykin (1970) |
| Vdovykin (1970) | |
China | |
| I. Leung and R. Winston et al. (47) |
Finland | |
| Vdovykin (4) |
France | |
| El Mendili et al. (2022) |
India | |
| Gennady P. Vdovykin (1970) +1 other reference |
| Gennady P. Vdovykin (1970) |
Kazakhstan | |
| Dubinchuk et al. (2010, January) |
| Shumilova et al. (2011, November) |
New Zealand | |
| Bunch et al. (Lonsdaleite) |
Russia | |
| Kvasnytsya et al. (2013) |
| Sonin et al. (Russia) +2 other references |
| Ohfuji et al. (2015) | |
| Gennady P. Vdovykin (1970) |
| chemistry and genesis et al. (in Russian) +1 other reference |
USA (TL) | |
| Frondel (1967a) +2 other references |
| Geochimica et Cosmochimica Acta |
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