General Keiviite-(Y) Information
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Chemical Formula: |
(Y,Yb)2Si2O7 |
Composition: |
Molecular Weight = 388.05 gm |
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Yttrium 34.37 % Y 43.64 % Y2O3 |
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Ytterbium 22.30 % Yb 25.39 % Yb2O3 |
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Silicon 14.48 % Si 30.97 % SiO2 |
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Oxygen 28.86 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
Y1.5Yb0.5Si2O7 |
IMA Status: |
Approved IMA 1985 |
Locality: |
Link to MinDat.org Location Data. |
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Search for Keiviite-(Y) Images |
Images:
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Keiviite-(Y) Crystallography
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Axial Ratios: |
a:b:c =0.7639:1:0.5283 |
Cell Dimensions: |
a = 6.845, b = 8.96, c = 4.734, Z = 2; beta = 101.65° V = 284.36 Den(Calc)= 4.53 |
Crystal System: |
Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m |
X Ray Diffraction: |
By Intensity(I/Io): 3.23(1), 4.65(0.9), 3.04(0.8), |
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Physical Properties of Keiviite-(Y)
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Cleavage: |
[110] Perfect, [001] Indistinct |
Color: |
Colorless, White, Pink brown. |
Density: |
4.45 |
Diaphaniety: |
Transparent |
Hardness: |
4-5 - Fluorite-Apatite |
Luster: |
Vitreous (Glassy) |
Streak: |
white |
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Optical Properties of Keiviite-(Y)
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Gladstone-Dale: |
CI meas= -0.012 (Superior) - where the CI = (1-KPDmeas/KC) CI calc= 0.006 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1633,KPDmeas= 0.1662,KC= 0.1642 |
Optical Data: |
Biaxial (-), a=1.713, b=1.748, g=1.758, bire=0.0450, 2V(Calc)=54, 2V(Meas)=55-56. |
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Calculated Properties of Keiviite-(Y)
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Electron Density: |
relectron=4.14 gm/cc note: rKeiviite-(Y) =4.53 gm/cc. |
Fermion Index |
Fermion Index = 0.0749 Boson Index = 0.9251 |
Photoelectric: |
PEKeiviite-(Y) = 261.05 barns/electron U=PEKeiviite-(Y) x relectron=1,081.85 barns/cc. |
Radioactivity: |
GRapi = 21,757.44 (Gamma Ray American Petroleum Institute Units)
Keiviite-(Y) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.
Estimated Radioactivity from Keiviite-(Y) - weak
Specimen Size Weight/Volume (Sphere) * |
Calculated Activity Bequerols (Bq) |
Calculated Activity Curies (Ci) |
Estimated Activity GR(api) |
Estimated Exposure (mRem**)/hr If Held in Hand For One Hour |
| 1000 gm / 7.50 cm |
499,438 |
1.35E-05 |
21,757.44 |
7.15 |
| 100 gm / 3.48 cm |
49,944 |
1.35E-06 |
2,175.74 |
0.72 |
| 10 gm / 1.62 cm |
4,994 |
1.35E-07 |
217.57 |
0.07 |
| 1 gm / 7.50 mm |
499 |
1.35E-08 |
21.76 |
0.01 |
| 0.1 gm / 3.48 mm |
50 |
1.35E-09 |
2.18 |
0.00 |
| 0.01 gm / 1.62 mm |
5 |
1.35E-10 |
0.22 |
0.00 |
| 0.001 gm / 0.75 mm |
0 |
1.35E-11 |
0.02 |
0.00 |
Weight of pure Keiviite-(Y) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.53 gm/cc.*
Goverment Estimate of Average Annual Exposure (
360 mRem)
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Note: 10 microsieverts/hr = 1 mRem/hr **
Max Permissable Adult Dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
Lethal Dose LD(50) Exposure 400,000 to 500,000 mRem
Estimated Thorium Activity ( 1.11 % Th) From Sum REE Elements (22.30 % REE)
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Keiviite-(Y) Classification
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Dana Class: |
55.2.1a.2 (55)Sorosilicate Si2O7 Groups, Generally with No Additional Anions |
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(55.2)with cations in [6] coordination |
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(55.2.1a)Thortveitite group |
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55.2.1a.1 Gittinsite CaZrSi2O7 C 2/m 2/m |
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55.2.1a.2 Keiviite-(Y) (Y,Yb)2Si2O7 C 2/m 2/m |
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55.2.1a.3 Keiviite-(Yb) (Yb,Y)2Si2O7 C 2/m 2/m |
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55.2.1a.4 Thortveitite (Sc,Y)2Si2O7 C 2/m 2/m |
Strunz Class: |
VIII/C.01-20 VIII - Silicates |
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VIII/C - Sorosilicates, with [Si2O7]6-, without anions unfamiliar to tetraheders |
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VIII/C.01 - Thortveitite - Rowlandite-(Y) series |
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VIII/C.01-10 Thortveitite (Sc,Y)2Si2O7 C 2/m 2/m |
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VIII/C.01-15 Gittinsite CaZrSi2O7 C 2/m 2/m |
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VIII/C.01-18 Kristiansenite! Ca2ScSn(Si2O7)(Si2O6OH) C1 1 |
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VIII/C.01-20 Keiviite-(Y) (Y,Yb)2Si2O7 C 2/m 2/m |
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VIII/C.01-30 Keiviite-(Yb) (Yb,Y)2Si2O7 C 2/m 2/m |
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VIII/C.01-40 Yttrialite-(Y) (Y,Th)2Si2O7 P 21/m 2/m |
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VIII/C.01-45 Percleveite-(Ce)! (Ce,La,Nd)2Si2O7 P 41 4 |
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VIII/C.01-50 Rowlandite-(Y) Y4FeSi4O14F2(?) None |
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Other Keiviite-(Y) Information
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References: |
PHYS. PROP.(Am.Min.,Vol.73,p191,1988) OPTIC PROP.(Am.Min.,Vol.73,p191,1988) |
See Also: |
Links to other databases for Keiviite-(Y) :
1 -Am. Min. Crystal Structure Database
2 -Athena
3 -Google Images
4 -Google Scholar
5 -Handbook of Mineralogy (MinSocAm)
6 -Handbook of Mineralogy (UofA)
7 -MinDAT
8 -MinMax(Deutsch)
9 -MinMax(English)
10 -Mineralienatlas (Deutsch)
11 -QUT Mineral Atlas
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Print or Cut-and-Paste your Keiviite-(Y) Specimen Label here :
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Keiviite-(Y)
(Y,Yb)2Si2O7
Dana No: 55.2.1a.2 Strunz No: VIII/C.01-20
Locality:
Notes:
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