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).
Type Locality:
Unique Identifiers
Mindat ID:
53754
Long-form identifier:
mindat:1:1:53754:6
GUID
(UUID V4):
(UUID V4):
6908f82e-42f8-4306-b9a5-dd618fa54657
IMA Classification of Percleveite-(La)
Approved
Approval year:
2019
First published:
2020
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 |
---|---|---|
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
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
Pleochroism:
Non-pleochroic
Chemistry of Percleveite-(La)
Mindat Formula:
La2Si2O7
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) |
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, A., Zubkova, N., Pekov, I., Chukanov, N., Škoda, R., Agakhanov, A., Belakovskiy, D.I., Ksenofontov, D.A., Plášil, J., Kuznetsov, A.M., Britvin, S.N., Pushcharovsky, D. (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.
Synonyms of Percleveite-(La)
Other Language Names for Percleveite-(La)
German:Percleveit-(La)
Related Minerals - Strunz-mindat Grouping
9.BC. | Kozłowskiite | Ca4Fe2+2Sn3(Si2O7)2(Si2O6OH)2 |
9.BC. | Anorthoyttrialite-(Y) | Y4(SiO4)(Si3O10) |
9.BC.05 | Gittinsite | CaZrSi2O7 |
9.BC.05 | Keiviite-(Y) | Y2Si2O7 |
9.BC.05 | Keiviite-(Yb) | Yb2Si2O7 |
9.BC.05 | Thortveitite | Sc2Si2O7 |
9.BC.05 | Yttrialite-(Y) | (Y,Th)2Si2O7 |
9.BC.10 | Keldyshite | (Na,H)2ZrSi2O7 |
9.BC.10 | Khibinskite | K2ZrSi2O7 |
9.BC.10 | Parakeldyshite | Na2ZrSi2O7 |
9.BC.15 | Rankinite | Ca3Si2O7 |
9.BC.20 | Barysilite | Pb8Mn2+[Si2O7]3 |
9.BC.25 | Edgarbaileyite | [Hg2]2+3[Si2O7] |
9.BC.30 | Kristiansenite | Ca4Sc2Sn2(Si2O7)2(Si2O6OH)2 |
9.BC.30 | Silesiaite | Ca4Fe3+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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References for Percleveite-(La)
Localities for Percleveite-(La)
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.
Austria | |
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Russia (TL) | |
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