Keiviite-(Yb) Mineral Data

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General Keiviite-(Yb) Information

Chemical Formula:

(Yb,Y)2Si2O7

Composition:

Molecular Weight = 472.18 gm

Yttrium 9.41 % Y 11.96 % Y₂O₃

Ytterbium 54.97 % Yb 62.59 % Yb₂O₃

Silicon 11.90 % Si 25.45 % SiO₂

Oxygen 23.72 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Yb_1.5Y_0.5Si₂O₇

Environment:

Found in an "amazonite" pegmatite with fluorite.

IMA Status:

Approved IMA 1983

Locality:

Keivy, Kola Peninsula, Russia Link to MinDat.org Location Data.

Name Origin:

Named for the locality and the ytterbium content.

Name Pronunciation:

Keiviite-(Yb)

Keiviite-(Yb) Image

Images:

Keiviite-(Yb)

Comments: White massive blebs of keiviite-(Yb) in blue-green fluorite.
Location: Mount Ploskaja, west Keivy, Kola, Russia. Scale: See Image.
© Rruff Database

Keiviite-(Yb) Crystallography

Axial Ratios:

a:b:c =0.7671:1:0.5321

Cell Dimensions:

a = 6.84, b = 8.916, c = 4.745, Z = 2; beta = 102.11° V = 282.94 Den(Calc)= 5.54

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.2(1), 3.24(1), 3.03(0.09),

Crystal Structure:

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Smolin Y I , Shepelev Y F , Acta Crystallographica, Section B , 26 (1970) p.484-492, The crystal structures of the rare earth pyrosilicates, Locality: synthetic

Physical Properties of Keiviite-(Yb)

Cleavage:

{???} Perfect

Color:

Colorless.

Density:

5.95

Diaphaneity:

Transparent

Hardness:

4-5 - Fluorite-Apatite

Luminescence:

Cathodoluminescence, Short UV=faint green.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Keiviite-(Yb)

Gladstone-Dale:

CI meas= 0.077 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.009 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1353,KPDmeas= 0.126,KC= 0.1365
Ncalc = 1.76 - 1.81

Optical Data:

Biaxial (-), a=1.723, b=1.758, g=1.768, bire=0.0450

Calculated Properties of Keiviite-(Yb)

Electron Density:

Bulk Density (Electron Density)=4.89 gm/cc
note: Specific Gravity of Keiviite-(Yb) =5.54 gm/cc.

Fermion Index:

Fermion Index = 0.17
Boson Index = 0.83

Photoelectric:

PE_{Keiviite-(Yb)}= 565.62 barns/electron
U=PE_{Keiviite-(Yb)} x r_electron=2,767.34 barns/cc.

Radioactivity:

GRapi = 51,783.07 (Gamma Ray American Petroleum Institute Units)
Concentration of Keiviite-(Yb) per GRapi unit = 19.31 (PPM)

Keiviite-(Yb) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 10 cm box) 587.39 ±146.85 grams of pure Keiviite-(Yb) .

**Estimated Radioactivity from Keiviite-(Yb)** - 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 / 7.01 cm	1,231,341	3.33E-05	51,783.07	17.02
100 gm / 3.25 cm	123,134	3.33E-06	5,178.31	1.70
10 gm / 1.51 cm	12,313	3.33E-07	517.83	0.17
1 gm / 7.01 mm	1,231	3.33E-08	51.78	0.02
0.1 gm / 3.25 mm	123	3.33E-09	5.18	0.00
0.01 gm / 1.51 mm	12	3.33E-10	0.52	0.00
0.001 gm / 0.70 mm	1	3.33E-11	0.05	0.00

Weight of pure Keiviite-(Yb) in grams (gm) and Calculated Diameter of a Sphere with a Density of 5.54 gm/cc.*
Goverment Estimate of Average Annual Exposure ( 360 mRem) **
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 ( 2.75 % Th) From Sum REE Elements (54.97 % REE)

Keiviite-(Yb) Classification

Dana Class:

55.02.01a.03 (55)Sorosilicate Si2O7 Groups, Generally with No Additional Anions

(55.02)with cations in [6] coordination

(55.02.01a)Thortveitite group

55.02.01a.01 Gittinsite CaZrSi2O7 C 2/m 2/m

55.02.01a.02 Keiviite-(Y) (Y,Yb)2Si2O7 C 2/m 2/m

55.02.01a.03 Keiviite-(Yb) (Yb,Y)2Si2O7 C 2/m 2/m

55.02.01a.04 Thortveitite (Sc,Y)2Si2O7 C 2/m 2/m

Strunz Class:

09.BC.05 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BC -Si2O7 groups, without non-tetrahedral anions;

09.BC.05 Keiviite-(Y) (Y,Yb)2Si2O7 C 2/m 2/m

09.BC.05 Gittinsite CaZrSi2O7 C 2/m 2/m

09.BC.05 Keiviite-(Yb) (Yb,Y)2Si2O7 C 2/m 2/m

09.BC.05 Thortveitite (Sc,Y)2Si2O7 C 2/m 2/m

09.BC.05 Yttrialite-(Y) (Y,Th)2Si2O7 P 2₁/m 2/m

Other Keiviite-(Yb) Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Keiviite-(Yb) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info
11 - WWW-MINCRYST

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Keiviite-(Yb)

(Yb,Y)2Si2O7
Dana No: 55.02.01a.03 Strunz No: 09.BC.05
Locality:

Notes: