Percleveite-(La)
A valid IMA mineral species
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Formula:
La2Si2O7
Colour:
Very pale yellow to colourless in thin fragments to light yellow in aggregates
Lustre:
Greasy
Hardness:
6
Specific Gravity:
5.094 (Calculated)
Crystal System:
Tetragonal
Name:
For being the La-dominant analogue of percleveite-(Ce).
In honour of Per Teodor Cleve (10 February 1840, Stockholm, Sweden - 18 June 1905, Uppsala, Sweden) - Swedish chemist, biologist, mineralogist, and oceanographer. He is best known for his discovery of the chemical elements holmium and thulium. Cleve earned his BSc and PhD from Uppsala University in 1863 and 1868, respectively. After receiving his PhD, he became an assistant professor of chemistry at the university. He later became professor of general and agricultural chemistry. In 1874, he theorised that didymium was in fact two elements; this theory was confirmed in 1885 when Carl Auer von Welsbach discovered neodymium and praseodymium.
In 1879 Cleve discovered holmium and thulium. His other contributions to chemistry include the discovery of aminonaphthalenesulfonic acids, also known as Cleve's acids. From 1890 on he focused on biological studies. He developed a method of determining the age and order of late glacial and postglacial deposits from the types of diatom fossils in the deposits, and wrote a seminal text in the field of oceanography.
In honour of Per Teodor Cleve (10 February 1840, Stockholm, Sweden - 18 June 1905, Uppsala, Sweden) - Swedish chemist, biologist, mineralogist, and oceanographer. He is best known for his discovery of the chemical elements holmium and thulium. Cleve earned his BSc and PhD from Uppsala University in 1863 and 1868, respectively. After receiving his PhD, he became an assistant professor of chemistry at the university. He later became professor of general and agricultural chemistry. In 1874, he theorised that didymium was in fact two elements; this theory was confirmed in 1885 when Carl Auer von Welsbach discovered neodymium and praseodymium.
In 1879 Cleve discovered holmium and thulium. His other contributions to chemistry include the discovery of aminonaphthalenesulfonic acids, also known as Cleve's acids. From 1890 on he focused on biological studies. He developed a method of determining the age and order of late glacial and postglacial deposits from the types of diatom fossils in the deposits, and wrote a seminal text in the field of oceanography.
Type Locality:
Unique Identifiers
Mindat ID:
53754
Long-form identifier:
mindat:1:1:53754:6
Similar Names
| Percleveite-(Ce) | A valid IMA mineral species | Ce2Si2O7 |
IMA Classification of Percleveite-(La)
Approved
Approval year:
2019
First published:
2020
Type description reference:
Kasatkin, Anatoly V., Zubkova, Natalia V., Pekov, Igor V., Chukanov, Nikita V., Škoda, Radek, Agakhanov, Atali A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitriy A., Plášil, Jakub, Kuznetsov, Aleksey M., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2020) The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part III. Percleveite-(La), La2Si2O7, a new REE disilicate mineral. Mineralogical Magazine, 84 (6) 913-920 doi:10.1180/mgm.2020.81
Classification of Percleveite-(La)
9.BC.35
9 : SILICATES (Germanates)
B : Sorosilicates
C : Si2O7 groups, without non-tetrahedral anions; cations in octahedral [6] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
C : Si2O7 groups, without non-tetrahedral anions; cations in octahedral [6] and greater coordination
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 |
|---|---|---|
| Pcv-La | 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 Percleveite-(La)
Greasy
Transparency:
Transparent
Colour:
Very pale yellow to colourless in thin fragments to light yellow in aggregates
Streak:
White
Hardness:
6 on Mohs scale
Hardness Data:
Measured
Comment:
Based on scratch tests
Tenacity:
Brittle
Cleavage:
Imperfect/Fair
Imperfect {001}
Imperfect {001}
Fracture:
Irregular/Uneven
Density:
5.094 g/cm3 (Calculated)
Comment:
Calculated from the empirical formula
Optical Data of Percleveite-(La)
Type:
Uniaxial (+)
RI values:
nω = 1.825(10) nε = 1.835(10)
Max. Birefringence:
δ = 0.010
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:
Moderate
Pleochroism:
Non-pleochroic
Chemistry of Percleveite-(La)
Mindat Formula:
La2Si2O7
Element Weights:
Elements listed:
Crystallography of Percleveite-(La)
Crystal System:
Tetragonal
Class (H-M):
4 - Pyramidal
Space Group:
P41
Cell Parameters:
a = 6.8482(3) Å, c = 24.8550(13) Å
Ratio:
a:c = 1 : 3.629
Unit Cell V:
1165.64 ų
Z:
8
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.194 Å | (18) |
| 3.564 Å | (16) |
| 3.349 Å | (16) |
| 3.157 Å | (100) |
| 3.043 Å | (22) |
| 2.934 Å | (39) |
| 2.893 Å | (29) |
| 2.864 Å | (21) |
Reference:
Kasatkin, Anatoly V., Zubkova, Natalia V., Pekov, Igor V., Chukanov, Nikita V., Škoda, Radek, Agakhanov, Atali A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitriy A., Plášil, Jakub, Kuznetsov, Aleksey M., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2020) The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part III. Percleveite-(La), La2Si2O7, a new REE disilicate mineral. Mineralogical Magazine, 84 (6) 913-920 doi:10.1180/mgm.2020.81
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 37 : Layered igneous intrusions and related PGE minerals |
Type Occurrence of Percleveite-(La)
General Appearance of Type Material:
Isolated anhedral grains commonly up to 0.2 × 0.4 mm and very rarely up to 1 × 1 mm.
Place of Conservation of Type Material:
In the collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18-2, Moscow 119071, Russia, registration number 5362/1
Geological Setting of Type Material:
Polymineralic REE-bearing nodules
Associated Minerals at Type Locality:
Reference:
Kasatkin, Anatoly V., Zubkova, Natalia V., Pekov, Igor V., Chukanov, Nikita V., Škoda, Radek, Agakhanov, Atali A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitriy A., Plášil, Jakub, Kuznetsov, Aleksey M., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2020) The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part III. Percleveite-(La), La2Si2O7, a new REE disilicate mineral. Mineralogical Magazine, 84 (6) 913-920 doi:10.1180/mgm.2020.81
Synonyms of Percleveite-(La)
Other Language Names for Percleveite-(La)
Dutch:Percleveiet-(La)
German:Percleveit-(La)
Related Minerals - Strunz-mindat Grouping
| 9.BC. | Anorthoyttrialite-(Y) | Y4(SiO4)(Si3O10) |
| 9.BC. | Kozłowskiite | Ca4(Fe2+Sn3)[Si2O7]2[Si2O6OH]2 |
| 9.BC.05 | Yttrialite-(Y) | (Y,Th)2Si2O7 |
| 9.BC.05 | Thortveitite | Sc2Si2O7 |
| 9.BC.05 | Keiviite-(Y) | Y2Si2O7 |
| 9.BC.05 | Keiviite-(Yb) | Yb2Si2O7 |
| 9.BC.05 | Gittinsite | CaZrSi2O7 |
| 9.BC.10 | Parakeldyshite | Na2ZrSi2O7 |
| 9.BC.10 | Keldyshite | (Na,H)2ZrSi2O7 |
| 9.BC.10 | Khibinskite | K2ZrSi2O7 |
| 9.BC.10 | Brunovskyite | NaZrSi2O6(OH) |
| 9.BC.15 | Rankinite | Ca3Si2O7 |
| 9.BC.20 | Barysilite | Pb8Mn2+[Si2O7]3 |
| 9.BC.25 | Edgarbaileyite | [Hg2]2+3[Si2O7] |
| 9.BC.30 | Kristiansenite | Ca4(Sc2Sn2)[Si2O7]2[Si2O6OH]2 |
| 9.BC.30 | Nybergite | Ca4Sc3Sn(Si2O7)(Si2O6OH)3 |
| 9.BC.30 | Silesiaite | Ca4(Fe3+2Sn2)[Si2O7]2[Si2O6OH]2 |
| 9.BC.35 | Percleveite-(Ce) | Ce2Si2O7 |
| 9.BC.40 | Scottyite | BaCu2Si2O7 |
Fluorescence of Percleveite-(La)
Does not fluoresce under ultraviolet light.
Other Information
Notes:
Does not react with either cold hydrochloric or nitric acids.
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 Percleveite-(La)
mindat.org URL:
https://www.mindat.org/min-53754.html
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Please feel free to link to this page.
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References for Percleveite-(La)
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2019) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) NEWSLETTER 51. European Journal of Mineralogy, 31 (5-6) 1099-1104 doi:10.1127/ejm/2019/0031-2894
Kasatkin, Anatoly V., Zubkova, Natalia V., Pekov, Igor V., Chukanov, Nikita V., Škoda, Radek, Agakhanov, Atali A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitriy A., Plášil, Jakub, Kuznetsov, Aleksey M., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2020) The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part III. Percleveite-(La), La2Si2O7, a new REE disilicate mineral. Mineralogical Magazine, 84 (6) 913-920 doi:10.1180/mgm.2020.81
Localities for Percleveite-(La)
Showing 2 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.
Austria | |
| Kolitsch et al. (2021) |
Russia (TL) | |
| Miyawaki et al. (2019) +2 other references |
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