Keiviite-(Yb)
A valid IMA mineral species
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About Keiviite-(Yb)
Formula:
Yb2Si2O7
Colour:
Colourless
Lustre:
Vitreous
Hardness:
4 - 5
Specific Gravity:
5.95
Crystal System:
Monoclinic
Member of:
Name:
Originally translated from Russian to keiviite but also appears as keivite and keivyite. The suffix was added later by the IMA to conform to the nomenclature for rare-earth-element bearing minerals. The root name is for the type locality, Keivy massif, Russia.
Unique Identifiers
Mindat ID:
2178
Long-form identifier:
mindat:1:1:2178:0
GUID
(UUID V4):
(UUID V4):
2691678d-0edc-47c6-b8f4-65864f8ba813
IMA Classification of Keiviite-(Yb)
Approved
IMA status notes:
Renamed by the IMA
First published:
1983
Classification of Keiviite-(Yb)
9.BC.05
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
55.2.1a.3
55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
2 : Si2O7 Groups, Generally with no Additional Anions with cations in [6] coordination
55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
2 : Si2O7 Groups, Generally with no Additional Anions with cations in [6] coordination
14.8.3
14 : Silicates not Containing Aluminum
8 : Silicates of Group III metals other than Al
14 : Silicates not Containing Aluminum
8 : Silicates of Group III metals other than Al
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 |
---|---|---|
Kvi-Yb | 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 Keiviite-(Yb)
Vitreous
Transparency:
Transparent
Colour:
Colourless
Streak:
White
Hardness:
4 - 5 on Mohs scale
Cleavage:
Perfect
perfect on {110}, imperfect on {001}
perfect on {110}, imperfect on {001}
Density:
5.95 g/cm3 (Measured) 5.99 g/cm3 (Calculated)
Optical Data of Keiviite-(Yb)
Type:
Biaxial (-)
RI values:
nα = 1.723 nβ = 1.758 nγ = 1.768
2V:
Measured: 58°
Max Birefringence:
δ = 0.045
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:
High
Dispersion:
r < v strong
Optical Extinction:
Z = b; X ∧ c = 3°-5°; Y ∧ a = 7°-8°.
Chemistry of Keiviite-(Yb)
Mindat Formula:
Yb2Si2O7
Elements listed:
Crystallography of Keiviite-(Yb)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 6.840(2) Å, b = 8.916(2) Å, c = 4.745(1) Å
β = 102.11(3)°
β = 102.11(3)°
Ratio:
a:b:c = 0.767 : 1 : 0.532
Unit Cell V:
282.94 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Elongated platy and prismatic crystals.
Twinning:
Polysynthetic - common.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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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) |
---|---|---|---|---|---|---|---|
0009370 | Keiviite-(Yb) | Smolin Y I, Shepelev Y F (1970) The crystal structures of the rare earth pyrosilicates Acta Crystallographica B26 484-492 | 1970 | synthetic | 0 | 293 | |
0015614 | Keiviite-(Yb) | Yakubovich O V, Simonov M A, Voloshin A V, Pakhomovsky Y A (1986) Crystal structure of keivite Yb2[Si2O7] Soviet Physics Doklady 31 930-932 | 1986 | Kola Peninsula, Russia | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
3.24 Å | (100) |
3.20 Å | (100) |
3.03 Å | (90) |
4.64 Å | (80) |
2.720 Å | (70) |
2.674 Å | (70) |
2.262 Å | (70) |
2.165 Å | (60) |
2.127 Å | (60b) |
1.692 Å | (60) |
5.36 Å | (50) |
1.920 Å | (50) |
1.578 Å | (50) |
Comments:
Mt. Ploskaya, Russia. Data from the type description.
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 4b: Highly evolved igneous rocks | >3.0 |
34 : Complex granite pegmatites |
Type Occurrence of Keiviite-(Yb)
General Appearance of Type Material:
Single crystals and intergrowths 0.1-0.8 mm.
Place of Conservation of Type Material:
A.E. Fersman Museum, Moscow, Russia.
Geological Setting of Type Material:
Microcline bearing pegmatites.
Associated Minerals at Type Locality:
Reference:
Voloshin, A.V., Pakhomovsky, Y.A., Tyusheva, F.N. (1983) Keiviite Yb2Si2O7 - a new ytterbium silicate from amazonitic pegmatites of the Kola Peninsula. Mineralogiceskij Zhurnal: 5: 94-99.
Synonyms of Keiviite-(Yb)
Other Language Names for Keiviite-(Yb)
German:Keiviit-(Yb)
Russian:Кейвиит-(Yb)
Relationship of Keiviite-(Yb) to other Species
Member of:
Other Members of this group:
Keiviite-(Y) | Y2Si2O7 | Mon. 2/m : B2/m |
Thortveitite | Sc2Si2O7 | Mon. 2/m : B2/m |
Yttrialite-(Y) | (Y,Th)2Si2O7 | Mon. 2/m : P21/m |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
4 photos of Keiviite-(Yb) associated with Fluorite | CaF2 |
4 photos of Keiviite-(Yb) associated with Yttrofluorite | (Ca1-xYx)F2+x where 0.05< x |
3 photos of Keiviite-(Yb) associated with Keiviite-(Y) | Y2Si2O7 |
1 photo of Keiviite-(Yb) associated with Amazonite | K(AlSi3O8) |
1 photo of Keiviite-(Yb) associated with Monazite-(Ce) | Ce(PO4) |
1 photo of Keiviite-(Yb) associated with Zinnwaldite |
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 | 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.35 | Percleveite-(La) | La2Si2O7 |
9.BC.40 | Scottyite | BaCu2Si2O7 |
Fluorescence of Keiviite-(Yb)
Faint green cathodoluminescence.
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 Keiviite-(Yb)
mindat.org URL:
https://www.mindat.org/min-2178.html
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References for Keiviite-(Yb)
Reference List:
Localities for Keiviite-(Yb)
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.
Norway | |
| Husdal (2008) |
Russia (TL) | |
| Voloshin A.V. et al. (1983) +2 other references |
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Ploskaya Mt, Western Keivy Massif, Keivy Mountains, Lovozersky District, Murmansk Oblast, Russia