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Kimuraite-(Y)
A valid IMA mineral species
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About Kimuraite-(Y)
Professor Kenjiro Kimura (1896-1988)
Formula:
Ca(Y,Nd)2(CO3)4 · 6H2O
Colour:
pale purple, light pink, white
Lustre:
Vitreous, Silky
Hardness:
2½
Specific Gravity:
2.6
Crystal System:
Orthorhombic
Member of:
Name:
For professor Kenjiro Kimura (1896-1988), Tokyo University.
Type Locality:
This page provides mineralogical data about Kimuraite-(Y).
Unique Identifiers
Mindat ID:
2208
Long-form identifier:
mindat:1:1:2208:4
Similar Names
| Cumbraite | A rock subtype | |
| Cámaraite | A valid IMA mineral species | Ba3Na(Fe2+,Mn)8Ti4(Si2O7)4O4(OH,F)7 |
| Komarite | A synonym of Willemseite |
IMA Classification of Kimuraite-(Y)
Approved
IMA Formula:
CaY2(CO3)4·6H2O
Approval year:
1984
Type description reference:
Classification of Kimuraite-(Y)
5.CC.15
5 : CARBONATES (NITRATES)
C : Carbonates without additional anions, with H2O
C : With rare earth elements (REE)
5 : CARBONATES (NITRATES)
C : Carbonates without additional anions, with H2O
C : With rare earth elements (REE)
15.4.5.1
15 : HYDRATED NORMAL CARBONATES
4 : AmBn(XO3)p·xH2O, with (m+n):p < 1:1
15 : HYDRATED NORMAL CARBONATES
4 : AmBn(XO3)p·xH2O, with (m+n):p < 1:1
11.8.10
11 : Carbonates
8 : Carbonates of the rare earths
11 : Carbonates
8 : Carbonates of the rare earths
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 |
|---|---|---|
| Kmu-Y | 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 Kimuraite-(Y)
Vitreous, Silky
Transparency:
Translucent
Comment:
Silky on cleavages
Colour:
Pale purple, light pink, white
Streak:
White
Hardness:
2½ on Mohs scale
Cleavage:
Perfect
on {010}
on {010}
Density:
2.6(1) g/cm3 (Measured) 2.98 g/cm3 (Calculated)
Optical Data of Kimuraite-(Y)
Type:
Biaxial (-)
RI values:
nα = 1.584(2) nβ = 1.612(2) nγ = 1.626(2)
2V:
Measured: 70° (5), Calculated: 68°
Max. Birefringence:
δ = 0.042
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:
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:
small
Chemistry of Kimuraite-(Y)
Mindat Formula:
Ca(Y,Nd)2(CO3)4 · 6H2O
Element Weights:
Crystallography of Kimuraite-(Y)
Crystal System:
Orthorhombic
Cell Parameters:
a = 9.2545(8) Å, b = 23.976(4) Å, c = 6.0433(7) Å
Ratio:
a:b:c = 0.386 : 1 : 0.252
Unit Cell V:
1,340.92 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Spherulitic aggregates of scaly tabular crystals.
Comment:
Point Group: 2/m 2/m 2/m, mm2, or 222.;Space Group: Immm, Imm2, I212121, or I222.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.06 Å | (100) |
| 6.02 Å | (40) |
| 3.76 Å | (30) |
| 5.93 Å | (20) |
| 4.01 Å | (20) |
| 2.05 Å | (12) |
| 4.87 Å | (10) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Kimuraite-(Y)
Place of Conservation of Type Material:
National Science Museum, Tokyo, Japan, M-24513; National Museum of Natural History, Washington, D.C., USA, 164269.
Geological Setting of Type Material:
Fissues in alkali olivine basalt
Associated Minerals at Type Locality:
Synonyms of Kimuraite-(Y)
Other Language Names for Kimuraite-(Y)
Relationship of Kimuraite-(Y) to other Species
Member of:
Other Members of Tengerite Group:
| Hizenite-(Y) | Ca2Y6(CO3)11 · 14H2O | Orth. |
| Lokkaite-(Y) | Ca(Y,Gd,Nd,Dy)4(CO3)7 · 9H2O | Orth. |
| Tengerite-(Y) | Y2(CO3)3 · 2-3H2O | Orth. mmm(2/m2/m2/m) : Pnnm |
Common Associates
Associations Based on Photo Data:
| 9 photos of Kimuraite-(Y) associated with Lokkaite-(Y) | Ca(Y,Gd,Nd,Dy)4(CO3)7 · 9H2O |
| 4 photos of Kimuraite-(Y) associated with Lanthanite-(Nd) | Nd2(CO3)3 · 8H2O |
| 3 photos of Kimuraite-(Y) associated with Thalénite-(Y) | Y3Si3O10F |
| 3 photos of Kimuraite-(Y) associated with Allanite-(Y) | (CaY)(AlAlFe2+)O[Si2O7][SiO4](OH) |
| 2 photos of Kimuraite-(Y) associated with Kozoite-(Nd) | Nd(CO3)(OH) |
| 2 photos of Kimuraite-(Y) associated with Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| 2 photos of Kimuraite-(Y) associated with Lanthanite | REE3+2(CO3)3 · 8H2O |
| 1 photo of Kimuraite-(Y) associated with Aragonite | CaCO3 |
| 1 photo of Kimuraite-(Y) associated with Ilmenite | Fe2+TiO3 |
| 1 photo of Kimuraite-(Y) associated with 'Hyalite' | SiO2 · nH2O |
Related Minerals - Strunz-mindat Grouping
| 5.CC. | Bainbridgeite-(NdCe) | Na2Ba2NdCe(CO3)6 · 3H2O |
| 5.CC. | Yuchuanite-(Y) | Y2(CO3)3 · H2O |
| 5.CC. | Alicewilsonite-(YCe) | Na2Sr2YCe(CO3)6 · 3H2O |
| 5.CC.05 | Donnayite-(Y) | NaCaSr3Y(CO3)6 · 3H2O |
| 5.CC.05 | Alicewilsonite-(YLa) | Na2Sr2YLa(CO3)6 · 3H2O |
| 5.CC.05 | Mckelveyite-(Nd) | NaCaBa3Nd(CO3)6 · 3H2O |
| 5.CC.05 | Mckelveyite-(Y) | NaCaBa3Y(CO3)6 · 3H2O |
| 5.CC.05 | Ewaldite | Ba(Na,Ca,Y,Ce,K)(CO3)2 · 2.6H2O |
| 5.CC.05 | 'UM1992-05-CO:CaCeLaNaSr' | (Sr,Na,Y,REE,Ca,Ba)2(CO3)2 · H2O |
| 5.CC.05 | Weloganite | Na2Sr3Zr(CO3)6 · 3H2O |
| 5.CC.05 | Mckelveyite Group | A3B3(CO3)6 · 3H2O |
| 5.CC.05 | Bainbridgeite-(YCe) | Na2Ba2YCe(CO3)6 · 3H2O |
| 5.CC.05 | 'Unnamed (MSH UK-37A)' | Sr3NaCaY(CO3)6 · 3H2O |
| 5.CC.10 | Tengerite-(Y) | Y2(CO3)3 · 2-3H2O |
| 5.CC.15 | Lokkaite-(Y) | Ca(Y,Gd,Nd,Dy)4(CO3)7 · 9H2O |
| 5.CC.15 | Hizenite-(Y) | Ca2Y6(CO3)11 · 14H2O |
| 5.CC.20 | Shomiokite-(Y) | Na3Y[CO3]3 · 3H2O |
| 5.CC.25 | Lanthanite-(Ce) | Ce2(CO3)3 · 8H2O |
| 5.CC.25 | Lanthanite-(La) | La2(CO3)3 · 8H2O |
| 5.CC.25 | Lanthanite-(Nd) | Nd2(CO3)3 · 8H2O |
| 5.CC.25 |
Kirigo, Hizen-cho, Karatsu City, Saga Prefecture, Japan