Petalite
A valid IMA mineral species - grandfathered
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About Petalite
Formula:
LiAl(Si4O10)
Colour:
Colourless, white, grey, pink
Lustre:
Vitreous
Hardness:
6½
Specific Gravity:
2.412 - 2.422
Crystal System:
Monoclinic
Name:
From the Greek "petalon" for leaf, in allusion to the perfect basal cleavage.
Type Locality:
Visit gemdat.org for Unique Identifiers
Mindat ID:
3171
Long-form identifier:
mindat:1:1:3171:0
Similar Names
| K-petalite | Valid as an unnamed mineral | KAlSi4O10 |
| Podolite | A synonym of 'Carbonate-rich Apatite' |
IMA Classification of Petalite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
LiAlSi4O10
Classification of Petalite
9.EF.05
9 : SILICATES (Germanates)
E : Phyllosilicates
F : Single nets with 6-membered rings, connected by M[4], M[8], etc.
9 : SILICATES (Germanates)
E : Phyllosilicates
F : Single nets with 6-membered rings, connected by M[4], M[8], etc.
72.6.1.1
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
6 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with tetrahedral Al cross-linking
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
6 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with tetrahedral Al cross-linking
16.1.1
16 : Silicates Containing Aluminum and other Metals
1 : Aluminosilicates of Li
16 : Silicates Containing Aluminum and other Metals
1 : Aluminosilicates of Li
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 |
|---|---|---|
| Ptl | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Ptl | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Pet | 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 Petalite
Vitreous
Transparency:
Transparent, Translucent
Comment:
Pearly on cleavage {001}
Colour:
Colourless, white, grey, pink
Streak:
White
Hardness:
6½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {001}
poor on {201}
Perfect on {001}
poor on {201}
Fracture:
Conchoidal
Density:
2.412 - 2.422 g/cm3 (Measured) 2.4 g/cm3 (Calculated)
Optical Data of Petalite
Type:
Biaxial (+)
RI values:
nα = 1.504 nβ = 1.51 nγ = 1.516
Max. Birefringence:
δ = 0.012
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Low (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (90°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (90°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r > v weak
Chemistry of Petalite
Mindat Formula:
LiAl(Si4O10)
Element Weights:
Elements listed:
Common Impurities:
Mg,Fe,Na,Ca,K,H2O
Crystallography of Petalite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/b
Cell Parameters:
a = 11.737 Å, b = 5.171 Å, c = 7.630 Å
β = 112.54°
β = 112.54°
Ratio:
a:b:c = 2.27 : 1 : 1.476
Unit Cell V:
427.71 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Tabular or elongated
Twinning:
Common on {001}, lamellar
Comment:
Non-reduced cell. Unit-cell parameters of reduced cell: a = 7.630, b = 5.17, c = 11.28 Å, 106.1°.
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) |
|---|---|---|---|---|---|---|---|
| 0020423 | Petalite | Ross N L, Zhao J, Slebodnick C, Spencer E C, Chakoumakos B C (2015) Petalite under pressure: Elastic behavior and phase stability American Mineralogist 100 714-721 | 2015 | Aracuai pegmatite district, Minas Gerais, Brazil | 0.0001 | 293 | |
| 0010850 | Petalite | Tagai T, Ried H, Joswig W, Korekawa M (1982) Kristallographische untersuchungen eines petalits mittels neutronenbeugung und transmissionselektronenmikroskopie Zeitschrift fur Kristallographie 160 159-170 |  | 1982 | Varutrask, Sweden | 0 | 293 |
| 0020424 | Petalite | Ross N L, Zhao J, Slebodnick C, Spencer E C, Chakoumakos B C (2015) Petalite under pressure: Elastic behavior and phase stability American Mineralogist 100 714-721 | 2015 | Aracuai pegmatite district, Minas Gerais, Brazil | 0.32 | 293 | |
| 0020425 | Petalite | Ross N L, Zhao J, Slebodnick C, Spencer E C, Chakoumakos B C (2015) Petalite under pressure: Elastic behavior and phase stability American Mineralogist 100 714-721 | 2015 | Aracuai pegmatite district, Minas Gerais, Brazil | 0.56 | 293 | |
| 0020426 | Petalite | Ross N L, Zhao J, Slebodnick C, Spencer E C, Chakoumakos B C (2015) Petalite under pressure: Elastic behavior and phase stability American Mineralogist 100 714-721 | 2015 | Aracuai pegmatite district, Minas Gerais, Brazil | 0.89 | 293 | |
| 0020427 | Petalite | Ross N L, Zhao J, Slebodnick C, Spencer E C, Chakoumakos B C (2015) Petalite under pressure: Elastic behavior and phase stability American Mineralogist 100 714-721 | 2015 | Aracuai pegmatite district, Minas Gerais, Brazil | 1.25 | 293 | |
| 0020428 | Petalite | Ross N L, Zhao J, Slebodnick C, Spencer E C, Chakoumakos B C (2015) Petalite under pressure: Elastic behavior and phase stability American Mineralogist 100 714-721 | 2015 | Aracuai pegmatite district, Minas Gerais, Brazil | 2.71 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.731 Å | (100) |
| 3.672 Å | (34) |
| 3.649 Å | (24) |
| 3.510 Å | (16) |
| 1.934 Å | (7) |
| 2.570 Å | (6) |
| 2.071 Å | (5) |
Comments:
Harare, Zimbabwe. ICDD 14-90.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Geological Setting:
Lithium-rich pegmatites.
Type Occurrence of Petalite
Synonyms of Petalite
Other Language Names for Petalite
Common Associates
Associations Based on Photo Data:
| 12 photos of Petalite associated with Lepidolite | |
| 7 photos of Petalite associated with Pollucite | (Cs,Na)2(Al2Si4O12) · 2H2O |
| 7 photos of Petalite associated with Albite | Na(AlSi3O8) |
| 6 photos of Petalite associated with Elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 5 photos of Petalite associated with Quartz | SiO2 |
| 4 photos of Petalite associated with Montmorillonite | (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O |
| 4 photos of Petalite associated with Microcline | K(AlSi3O8) |
| 3 photos of Petalite associated with Montebrasite | LiAl(PO4)(OH) |
| 3 photos of Petalite associated with Nigerite Group | |
| 3 photos of Petalite associated with 'Cleavelandite' | Na(AlSi3O8) |
Related Minerals - Strunz-mindat Grouping
| 9.EF.10 | Sanbornite | BaSi2O5 |
| 9.EF.15 | Searlesite | Na(H2BSi2O7) |
| 9.EF.20 | Silinaite | NaLiSi2O5 · 2H2O |
| 9.EF.25 | Kanemite | HNaSi2O5 · 3H2O |
| 9.EF.30 | Yakovenchukite-(Y) | K3NaCaY2[Si12O30] · 4H2O |
Other Information
Thermal Behaviour:
Thermoluminescent
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
Lithium ore
Petalite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Petalite
mindat.org URL:
https://www.mindat.org/min-3171.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Petalite
Reference List:
Nel, H. J. (1946) Petalite and amblygonite from Karibib, South West Africa. American Mineralogist, 31 (1-2) 51-57
ROY, RUSTUM, ROY, DELLA M., OSBORN, E. F. (1950) Compositional and Stability Relationships Among the Lithium Aluminosilicates: Eucryptite, Spodumene, and Petalite. Journal of the American Ceramic Society, 33 (5). 152-159 doi:10.1111/j.1151-2916.1950.tb12780.x
Zemann-Hedlik, Anna, Zemann, J. (1954) Zur Kenntnis der Kristallstruktur von Petalit. Die Naturwissenschaften, 41 (20). 476-477 doi:10.1007/bf00628802
Zemann-Hedlik, A., Zemann, J. (1955) Die Kristallstruktur von Petalit, LiAlSi4O10. Acta Crystallographica, 8 (12) 781-787 doi:10.1107/s0365110x55002405
Effenberger, Herta (1980) Petalit, LiAlSi4O10: Verfeinerung der Kristallstruktur, Diskussion der Raumgruppe und Infrarot-Messung. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 27 (2). 129-142 doi:10.1007/bf01082403
Tagai, Tokuhei, Ried, Holger, Joswig, Werner, Korekawa, Masaaki (1982) Kristallographische Untersuchungen eines Petalits mittels Neutronenbeugung und Transmissionselektronenmikroskopie. Zeitschrift für Kristallographie, 160 (3). 159-170 doi:10.1524/zkri.1982.160.3-4.159
Černý, P.; London, D. (1983) Crystal chemistry and stability of petalite. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 31 (1-2). 81-96 doi:10.1007/bf01084763
Effenberger, H.; Fuess, H.; Müller, G.; Vogt, T. (1991) Crystal structure and hydrogen bonding in Li/H-exchanged petalite, HAlSi4O10. Zeitschrift für Kristallographie, 197 (1). 27-40 doi:10.1524/zkri.1991.197.1-2.27
Charoy, B., Noronha, F., Lima, A. (2001) Spodumene – petalite – eucryptite: mutual relationships and pattern of alteration in Li-rich aplite-pegmatite dykes from northern Portugal. The Canadian Mineralogist, 39 (3). 729-746 doi:10.2113/gscanmin.39.3.729
Shannon, Robert D., Shannon, Ruth C., Medenbach, Olaf, Fischer, Reinhard X. (2002) Refractive Index and Dispersion of Fluorides and Oxides. Journal of Physical and Chemical Reference Data, 31 (4) 931-970 doi:10.1063/1.1497384
Cressey, G. (2004) W.A. Deer, R.A. Howie, W.S. Wise and J. Zussman. Rock-Forming Minerals. Volume 4B. Second Edition. Framework Silicates: Silica Minerals, Feldspathoids and the Zeolites.
London (The Geological Society) 2004, xv + 982 pp. £125 (£62.50 to GSL members) ISBN 1-86239-144-0. Hardback. Mineralogical Magazine, 68 (5) 831-832 doi:10.1180/0680831pp.271-275
Localities for Petalite
Showing 192 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.
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Utö Mines, Utö, Haninge, Stockholm County, Sweden