Gadolinite-(Y)
A valid IMA mineral species - grandfathered
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About Gadolinite-(Y)
Johan Gadolin
Formula:
Y2Fe2+Be2Si2O10
Often slightly radioactive due to minor U and/or Th contents; therefore often metamict.
Colour:
Black, greenish-black, brown
Lustre:
Vitreous, Greasy
Hardness:
6½ - 7
Specific Gravity:
4.36 - 4.77
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of Johan Gadolin (5 June 1760, Turku, Finland - 15 August 1852, Mynämäki, Finland), chemist, physicist, and mineralogist. He discovered what would be the element yttrium, the first rare earth discovered. The "-(Y)" suffix was added in 1987 and is for to the predominance of yttrium as the REE in the composition.
Type Locality:
The yttrium analogue of gadolinite-(Ce) and Gadolinite-(Nd).
Difficult to distinguish from hingganite-(Y).
Difficult to distinguish from hingganite-(Y).
Unique Identifiers
Mindat ID:
1628
Long-form identifier:
mindat:1:1:1628:1
Similar Names
| Catalinite | A variety of 'Jasper' | SiO2 |
| Catlinite | A variety of 'Argillite' | |
| Gadolinite | A group of related mineral species | |
| Gadolinite-(Ce) | A valid IMA mineral species | (Ce,La,Nd,Y)2Fe2+Be2Si2O10 |
| Gadolinite-(Nd) | A valid IMA mineral species | Nd2Fe2+Be2O2(SiO4)2 |
IMA Classification of Gadolinite-(Y)
Approved, 'Grandfathered' (first described prior to 1959)
IMA status notes:
Renamed by the IMA
IMA Formula:
Fe2+Be2Y2(SiO4)2O2
First published:
1788
Approval history:
IMA 26-A: Definition of a gadolinite-(Y) neotype (Dan Holtstam, Alice Taddei, Hans-Jürgen Förster and Oona Appelt) Proposal 26-A is accepted, and the neotype material for gadolinite-(Y) is redefined from the Ytterby locality, Sweden. The sample is stored in the collections of the Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden, catalogue no. GEO-NRM LK6893
Classification of Gadolinite-(Y)
9.AJ.20
9 : SILICATES (Germanates)
A : Nesosilicates
J : Nesosilicates with BO3 triangles and/or B[4], Be[4] tetrahedra, cornersharing with SiO4
9 : SILICATES (Germanates)
A : Nesosilicates
J : Nesosilicates with BO3 triangles and/or B[4], Be[4] tetrahedra, cornersharing with SiO4
54.2.1b.3
54 : NESOSILICATES Borosilicates and Some Beryllosilicates
2 : Borosilicates and Some Beryllosilicates with B in [4] coordination
54 : NESOSILICATES Borosilicates and Some Beryllosilicates
2 : Borosilicates and Some Beryllosilicates with B in [4] coordination
14.3.23
14 : Silicates not Containing Aluminum
3 : Silicates of Be
14 : Silicates not Containing Aluminum
3 : Silicates of Be
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 |
|---|---|---|
| Gad-Y | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Gad | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
Physical Properties of Gadolinite-(Y)
Vitreous, Greasy
Transparency:
Opaque
Colour:
Black, greenish-black, brown
Streak:
Grayish green
Hardness:
6½ - 7 on Mohs scale
Tenacity:
Brittle
Fracture:
Splintery, Conchoidal
Density:
4.36 - 4.77 g/cm3 (Measured) 4.41 g/cm3 (Calculated)
Optical Data of Gadolinite-(Y)
Type:
Biaxial (+)
RI values:
nα = 1.77 nβ = 1.79 nγ = 1.82
2V:
Measured: 85°
Max. Birefringence:
δ = 0.050
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:
Very High (positive)
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.
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.
Dispersion:
r > v distinct
Chemistry of Gadolinite-(Y)
Mindat Formula:
Y2Fe2+Be2Si2O10
Often slightly radioactive due to minor U and/or Th contents; therefore often metamict.
Often slightly radioactive due to minor U and/or Th contents; therefore often metamict.
Element Weights:
Crystallography of Gadolinite-(Y)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Cell Parameters:
a = 10.000(2) Å, b = 7.565(2) Å, c = 4.768(1) Å
β = 90.31(2)°
β = 90.31(2)°
Ratio:
a:b:c = 1.322 : 1 : 0.63
Unit Cell V:
360.69 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Prismatic, massive
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) |
|---|---|---|---|---|---|---|---|
| 0004599 | Gadolinite-(Y) | Camara F, Oberti R, Ottolini L, Ventura G D, Bellatreccia F (2008) The crystal chemistry of Li in gadolinite American Mineralogist 93 996-1004 |  | 2008 | Vico lake, Latium, Italy | 0 | 293 |
| 0005292 | Gadolinite-(Y) | Demartin F, Pilati T, Diella V, Gentile P, Gramaccioli C M (1993) A crystal-chemical investigation of alpine gadolinite The Canadian Mineralogist 31 127-136 | | 1993 | Glogstafelberg, Val Formazza, Italy | 0 | 293 |
| 0005291 | Gadolinite-(Y) | Demartin F, Pilati T, Diella V, Gentile P, Gramaccioli C M (1993) A crystal-chemical investigation of alpine gadolinite The Canadian Mineralogist 31 127-136 | | 1993 | Monte Bassetta, Val Vigezzo, Italy | 0 | 293 |
| 0005290 | Gadolinite-(Y) | Demartin F, Pilati T, Diella V, Gentile P, Gramaccioli C M (1993) A crystal-chemical investigation of alpine gadolinite The Canadian Mineralogist 31 127-136 | | 1993 | "Bosco", Val Vigezzo, Italy | 0 | 293 |
| 0005289 | Gadolinite-(Y) | Demartin F, Pilati T, Diella V, Gentile P, Gramaccioli C M (1993) A crystal-chemical investigation of alpine gadolinite The Canadian Mineralogist 31 127-136 | | 1993 | "Strada", Val Vigezzo, Italy | 0 | 293 |
| 0005288 | Gadolinite-(Y) | Demartin F, Pilati T, Diella V, Gentile P, Gramaccioli C M (1993) A crystal-chemical investigation of alpine gadolinite The Canadian Mineralogist 31 127-136 | | 1993 | Val Nalps, Switzerland | 0 | 293 |
| 0005287 | Gadolinite-(Y) | Demartin F, Pilati T, Diella V, Gentile P, Gramaccioli C M (1993) A crystal-chemical investigation of alpine gadolinite The Canadian Mineralogist 31 127-136 | | 1993 | Beura, Ossola, Italy | 0 | 293 |
| 0005286 | Gadolinite-(Y) | Demartin F, Pilati T, Diella V, Gentile P, Gramaccioli C M (1993) A crystal-chemical investigation of alpine gadolinite The Canadian Mineralogist 31 127-136 | | 1993 | Moos, Rauris, Austria | 0 | 293 |
| 0000960 | Gadolinite-(Y) | Miyawaki R, Nakai I, Nagashima K (1984) A refinement of the crystal structure of gadolinite American Mineralogist 69 948-953 | | 1984 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.818 Å | (100) |
| 2.816 Å | (100) |
| 4.735 Å | (80) |
| 2.932 Å | (70) |
| 2.558 Å | (60) |
| 2.539 Å | (55) |
| 3.118 Å | (50) |
Comments:
Synthetic. The data are from Ito and Hafner (1974).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Geological Setting:
Granites and alkalic granitic pegmatites
Type Occurrence of Gadolinite-(Y)
Place of Conservation of Type Material:
stored in the collections of the Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden, catalogue no. GEO-NRM LK6893
Synonyms of Gadolinite-(Y)
Other Language Names for Gadolinite-(Y)
Dutch:Gadoliniet-(Y)
Russian:Гадолинит-(Y)
Simplified Chinese:硅铍钇矿
Swedish:Yttersten
Traditional Chinese:矽鈹釔礦
Varieties of Gadolinite-(Y)
| Calciogadolinite-(Y) | A Ca-dominant gadolinite. Although Ca dominates over any individual REE, the current site dominance rules do not allow for species status because trivalent elements (mostly REE) dominate over total divalent elements (mostly Ca) on the site. |
Relationship of Gadolinite-(Y) to other Species
Member of:
Other Members of Gadolinite:
| Gadolinite-(Ce) | (Ce,La,Nd,Y)2Fe2+Be2Si2O10 | Mon. 2/m |
| Gadolinite-(Nd) | Nd2Fe2+Be2O2(SiO4)2 | Mon. 2/m : P21/b |
Common Associates
Associations Based on Photo Data:
| 32 photos of Gadolinite-(Y) associated with Quartz | SiO2 |
| 14 photos of Gadolinite-(Y) associated with Hingganite-(Y) | (Y,REE,Ca)2(◻,Fe2+)Be2[SiO4]2(OH)2 |
| 13 photos of Gadolinite-(Y) associated with Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
| 13 photos of Gadolinite-(Y) associated with Microcline | K(AlSi3O8) |
| 12 photos of Gadolinite-(Y) associated with Allanite-(Ce) | (CaCe)(AlAlFe2+)O[Si2O7][SiO4](OH) |
| 11 photos of Gadolinite-(Y) associated with Fluorite | CaF2 |
| 10 photos of Gadolinite-(Y) associated with Orthoclase | K(AlSi3O8) |
| 9 photos of Gadolinite-(Y) associated with Tengerite-(Y) | Y2(CO3)3 · 2-3H2O |
| 8 photos of Gadolinite-(Y) associated with Anatase | TiO2 |
| 7 photos of Gadolinite-(Y) associated with 'Yttrofluorite' | (Ca1-xYx)F2+x where 0.05 < x < 0.3 |
Related Minerals - Strunz-mindat Grouping
| 9.AJ. | Hingganite-(Nd) | Nd2◻Be2Si2O8(OH)2 |
| 9.AJ. | Arrheniusite-(Ce) | CaMg[(Ce7Y3)Ca5](SiO4)4(Si2B3AsO18)(BO3)F11 |
| 9.AJ.05 | Ominelite | (Fe2+,Mg)(Al,Fe3+)3(SiO4)(BO3)O2 |
| 9.AJ.05 | Grandidierite | (Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2 |
| 9.AJ.10 | Dumortierite | Al(Al2O)(Al2O)2(SiO4)3(BO3) |
| 9.AJ.10 | Nioboholtite | (Nb0.6◻0.4)Al6BSi3O18 |
| 9.AJ.10 | Titanoholtite | (Ti0.75◻0.25)Al6BSi3O18 |
| 9.AJ.10 | Holtite | (Ta0.6◻0.4)Al6BSi3O18(O,OH)2.25 |
| 9.AJ.10 | Magnesiodumortierite | Mg(Al2OH)(Al2O)2(SiO4)3(BO3) |
| 9.AJ.15 | Garrelsite | Ba3NaSi2B7O16(OH)4 |
| 9.AJ.20 | 'Muromontite' | near Be2FeY2Si3O12 |
| 9.AJ.20 | Gadolinite-(Nd) | Nd2Fe2+Be2O2(SiO4)2 |
| 9.AJ.20 | Datolite | CaB(SiO4)(OH) |
| 9.AJ.20 | Melanocerite-(Ce) | (Ce,Ca)5(SiO4,BO4)3(OH,O) |
| 9.AJ.20 | Gadolinite-(Ce) | (Ce,La,Nd,Y)2Fe2+Be2Si2O10 |
| 9.AJ.20 | 'Unnamed (OH-analogue of Gadolinite-(Y))' | (Y,Ca)2(Fe,◻)Be2Si2O8(OH,O)2 |
| 9.AJ.20 | Hingganite-(Ce) | (Ce,REE)2(◻,Fe2+)Be2[SiO4]2(OH)2 |
| 9.AJ.20 | Hingganite-(Y) | (Y,REE,Ca)2(◻,Fe2+)Be2[SiO4]2(OH)2 |
| 9.AJ.20 | Hingganite-(Yb) | (Yb,Y,REE)2◻Be2[SiO4]2(OH)2 |
| 9.AJ.20 | Homilite | Ca2(Fe2+,Mg)B2Si2O10 |
| 9.AJ.20 | 'Minasgeraisite-(Y)' | (Ca2Y2)◻2(Be2B2)[SiO4]4(OH)4 |
| 9.AJ.20 | Calcybeborosilite-(Y) | (Y,Ca)2(◻,Fe2+)(B,Be)2[SiO4]2(OH,O)2 |
| 9.AJ.25 | Stillwellite-(La) | LaBSiO5 |
| 9.AJ.25 | Stillwellite-(Ce) | (Ce,La,Ca)BSiO5 |
| 9.AJ.30 | Cappelenite-(Y) | Ba(Y,Ce)6Si3B6O24F2 |
| 9.AJ.35 | Laptevite-(Ce) | Ca6(Fe2+,Mn2+)Y3REE7(SiO4)3(PO4)(B3Si3O18)(BO3)F11 |
| 9.AJ.35 | Proshchenkoite-(Y) | Ca(Y,REE,Ca,Na,Mn)15Fe2+(P,Si)Si6B3O34F14 |
| 9.AJ.35 | Okanoganite-(Y) | (Na,Ca)3(Y,Ce)12Si6B2O27F14 |
| 9.AJ.35 | Hundholmenite-(Y) | (Y,REE,Ca,Na)15(Al,Fe3+)(CaxAs3+1-x)(Si,As5+)Si6B3(O,F)48 |
| 9.AJ.35 | Vicanite-(Ce) | (Ca,Ce,La,Th)15As5+(As3+0.5,Na0.5)Fe3+Si6B4O40F7 |
| 9.AJ.40 | Jadarite | LiNaSiB3O7(OH) |
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 Gadolinite-(Y)
mindat.org URL:
https://www.mindat.org/min-1628.html
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References for Gadolinite-(Y)
Reference List:
Klaproth, M. H. (1802) LXXVI. Chemische Untersuchung des Gadolinits. In Beiträge zur chemischen Kenntniss der Mineralkörper Vol. 3. Rottmann. p.52-79.
Levinson, A. A. (1966) A system of nomenclature for rare-earth minerals. American Mineralogist, 51 (1-2) 152-158
Ito, Jun, Hafner, and Stefan S. (1974) Synthesis and study of gadolinites. American Mineralogist, 59 (7-8) 700-708
Miyawaki, Ritsuro, Nakai, Izumi, Nagashima, Kozo (1984) A refinement of the crystal structure of gadolinite. American Mineralogist, 69 (9-10) 948-953 [gadolinite-(Y)]
Nickel, Ernest H., Mandarino, Joseph A. (1987) Procedures involving the IMA Commission on New Minerals and Mineral Names and guidelines on mineral nomenclature. American Mineralogist, 72 (9-10) 1031-1042
Holtstam, D., Andersson, U. B. (2007) The REE minerals of the Bastnäs-type deposits, South-Central Sweden. The Canadian Mineralogist, 45 (5) 1073-1114 doi:10.2113/gscanmin.45.5.1073
Camara, F., Oberti, R., Ottolini, L., Della Ventura, G., Bellatreccia, F. (2008) The crystal chemistry of Li in gadolinite. American Mineralogist, 93 (7) 996-1004 doi:10.2138/am.2008.2748
Malczewski, D. (2010) Recrystallization in fully metamict gadolinite from Ytterby (Sweden), annealed in air and studied by 57Fe Mossbauer spectroscopy. American Mineralogist, 95 (4) 463-471 doi:10.2138/am.2010.3253
Localities for Gadolinite-(Y)
Showing 227 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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Iveland, Agder, Norway