Iwashiroite-(Y)
A valid IMA mineral species
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About Iwashiroite-(Y)
Formula:
Y(Ta,Nb)O4
Colour:
Dark red-brown, amber brown to brown
Lustre:
Sub-Adamantine, Vitreous
Hardness:
6
Specific Gravity:
7.1 (Calculated)
Crystal System:
Monoclinic
Name:
Iwashiro was an old name for the district, and is still the name of a neighboring town. The suffix/modifier follows the Levinson rule for minerals with essential REE, indicating a predominance of yttrium.
Type Locality:
Polymorph of:
Only one specimen found, in reddish feldspar in pegmatite.
Zoned (U-rich parts are metamict). Also known as a synthetic compound (M'-type YTaO4; Wolten, 1967).
See also formanite-(Y) and yttrotantalite-(Y).
The structure typically consist of TaO6 octahedra and YO8 polyhedra.
Zoned (U-rich parts are metamict). Also known as a synthetic compound (M'-type YTaO4; Wolten, 1967).
See also formanite-(Y) and yttrotantalite-(Y).
The structure typically consist of TaO6 octahedra and YO8 polyhedra.
Unique Identifiers
Mindat ID:
25650
Long-form identifier:
mindat:1:1:25650:8
IMA Classification of Iwashiroite-(Y)
Classification of Iwashiroite-(Y)
7.GA.10
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
G : Molybdates, Wolframates and Niobates
A : Without additional anions or H2O
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
G : Molybdates, Wolframates and Niobates
A : Without additional anions or H2O
Dana 7th ed.:
8.1.2.4
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 |
|---|---|---|
| Iwa-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 Iwashiroite-(Y)
Sub-Adamantine, Vitreous
Transparency:
Translucent
Colour:
Dark red-brown, amber brown to brown
Streak:
Pale brown
Hardness:
6 on Mohs scale
Cleavage:
Distinct/Good
on {010}, poor on {001}
on {010}, poor on {001}
Density:
7.1 g/cm3 (Calculated)
Optical Data of Iwashiroite-(Y)
Reflectivity:
| Wavelength | R1 (%) | R2 (%) | imR1 (%) | imR2 (%) |
|---|---|---|---|---|
| 400nm | 14.4% | 15.3% | 5.2% | 5.2% |
| 420nm | 14.3% | 14.9% | 4.4% | 4.6% |
| 440nm | 14.0% | 14.4% | 4.2% | 4.4% |
| 460nm | 13.9% | 14.2% | 4.1% | 4.3% |
| 470nm | 13.8% | 14.1% | 4.1% | 4.4% |
| 480nm | 13.7% | 14.0% | 4.1% | 4.4% |
| 500nm | 13.7% | 13.9% | 4.1% | 4.4% |
| 520nm | 13.5% | 13.8% | 4.0% | 4.4% |
| 540nm | 13.5% | 13.8% | 4.0% | 4.5% |
| 546nm | 13.6% | 13.8% | 4.0% | 4.5% |
| 560nm | 13.6% | 13.8% | 4.1% | 4.6% |
| 580nm | 13.6% | 13.9% | 4.1% | 4.7% |
| 589nm | 13.6% | 13.9% | 4.2% | 4.8% |
| 600nm | 13.7% | 13.9% | 4.3% | 4.8% |
| 620nm | 13.8% | 14.0% | 4.5% | 5.0% |
| 640nm | 13.7% | 14.0% | 4.6% | 5.1% |
| 650nm | 13.7% | 14.0% | 4.6% | 5.0% |
| 660nm | 13.8% | 14.0% | 4.7% | 5.1% |
| 680nm | 13.9% | 14.1% | 5.0% | 5.3% |
| 700nm | 14.1% | 14.3% | 5.8% | 5.9% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 15.3%.
R1 shown in black, R2 shown in red, imR1 shown in green, imR2 shown in blue
Comments:
Refractive indices could not be measured due to the very small dimensions of the crystals and the association with a metamict substance.
Chemistry of Iwashiroite-(Y)
Mindat Formula:
Y(Ta,Nb)O4
Element Weights:
Elements listed:
Common Impurities:
REE,Ti,U
Crystallography of Iwashiroite-(Y)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/b
Setting:
P2/a
Cell Parameters:
a = 5.262 Å, b = 5.451 Å, c = 5.11 Å
β = 95.12°
β = 95.12°
Ratio:
a:b:c = 0.965 : 1 : 0.937
Unit Cell V:
146 ų
Z:
2
Comment:
M'-type YTaO4 modification.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.13 Å | (100) |
| 2.95 Å | (94) |
| 2.73 Å | (26) |
| 1.890 Å | (29) |
| 1.862 Å | (29) |
Comments:
Format: d/Å (I/%) (hkl)
From type description
From 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 Iwashiroite-(Y)
General Appearance of Type Material:
Aggregate of small euhedral platy crystals.
Place of Conservation of Type Material:
National Science Museum, Tokyo, Japan, NSM-M28537.
Geological Setting of Type Material:
Yttrium-rich granite pegmatite.
Associated Minerals at Type Locality:
Synonyms of Iwashiroite-(Y)
Other Language Names for Iwashiroite-(Y)
Dutch:Iwashiroiet-(Y)
German:Iwashiroit-(Y)
Japanese:岩代石
Simplified Chinese:斜方钽钇矿
Traditional Chinese:斜方鉭釔礦
Related Minerals - Strunz-mindat Grouping
| 7.GA. | Yunhaoite | K2(MoO4) |
| 7.GA.05 | Ronpetersonite | BaWO4 |
| 7.GA.05 | Fergusonite-(Ce) | CeNbO4 · 0.3H2O |
| 7.GA.05 | 'Fergusonite-(Nd)' | NdNbO4 |
| 7.GA.05 | Fergusonite-(Y) | YNbO4 |
| 7.GA.05 | Powellite | Ca(MoO4) |
| 7.GA.05 | Stolzite | Pb(WO4) |
| 7.GA.05 | Suseinargiuite | NaBi(MoO4)2 |
| 7.GA.05 | Wulfenite | Pb(MoO4) |
| 7.GA.05 | Scheelite | Ca(WO4) |
| 7.GA.10 | Formanite-(Y) | YTaO4 |
| 7.GA.15 | Paraniite-(Y) | Ca2Y(AsO4)(WO4)2 |
| 7.GA.20 | Takanawaite-(Y) | YTaO4 |
Fluorescence of Iwashiroite-(Y)
Not fluorescent.
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 Iwashiroite-(Y)
mindat.org URL:
https://www.mindat.org/min-25650.html
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References for Iwashiroite-(Y)
Reference List:
Wolten, G. M. (1967) The structure of the M'-phase of YTaO4, a third fergusonite polymorph. Acta Crystallographica, 23 (6) 939-944 doi:10.1107/s0365110x67004098
Hori, Hidemichi, Kobayashi, Toshinori, Miyawaki, Ritsuro, Matsubara, Satoshi, Yokoyama, Kazumi, Shimizu, Masaaki (2006) Iwashiroite-(Y), YTaO4, a new mineral from Suishoyama, Kawamata Town, Fukushima Prefecture, Japan. Journal of Mineralogical and Petrological Sciences, 101 (4) 170-177 doi:10.2465/jmps.101.170
Localities for Iwashiroite-(Y)
Showing 1 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.
Japan (TL) | |
| Hori et al. (2006) +1 other reference |
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Suishoyama pegmatite, Iizaka Village, Kawamata, Date District, Fukushima Prefecture, Japan