Yttrialite-(Y) Mineral Data

General Yttrialite-(Y) Information

Chemical Formula:

(Y,Th)2Si2O7

Composition:

Molecular Weight = 417.54 gm

Yttrium 31.94 % Y 40.56 % Y₂O₃

Thorium 27.79 % Th 31.62 % ThO₂

Silicon 13.45 % Si 28.78 % SiO₂

Oxygen 26.82 % O

______ ______

100.00 % 100.96 % = TOTAL OXIDE

Empirical Formula:

Y_1.5Th_0.5Si₂O₇

Environment:

A late-stage mineral in some rare-earth-bearing pegmatites. Associated with gadolinite.

IMA Status:

Valid Species (Pre-IMA) 1889

Locality:

Baringer Hill pegmatite, 26 km west of Burnet, and from Rode Ranch, near Bluï¿½ton, Llano County, Texas, USA. Link to MinDat.org Location Data.

Name Origin:

Named for the yttrium in its composition.

Name Pronunciation:

Yttrialite-(Y) + Pronunciation

Synonym:

ICSD 28004

PDF 24-1427

Yttrialite-(Y) Crystallography

Axial Ratios:

a:b:c =0.9106:1:0.6228

Cell Dimensions:

a = 7.34, b = 8.06, c = 5.02, Z = 2; beta = 108.5° V = 281.64 Den(Calc)= 4.92

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/m

Physical Properties of Yttrialite-(Y)

Cleavage:

None

Color:

Green, Orangish yellow.

Density:

4.58

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

5-5.5 - Apatite-Knife Blade

Luminescence:

Non-fluorescent.

Optical Properties of Yttrialite-(Y)

Gladstone-Dale:

CI meas= 0.089 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.152 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1541,KPDmeas= 0.1655,KC= 0.1816
Ncalc = 1.83 - 1.89

Optical Data:

Isotropic, n=1.758.

Calculated Properties of Yttrialite-(Y)

Electron Density:

Bulk Density (Electron Density)=4.11 gm/cc
note: Specific Gravity of Yttrialite-(Y) =4.58 gm/cc.

Fermion Index:

Fermion Index = 0.0064114338
Boson Index = 0.9935885662

Photoelectric:

PE_{Yttrialite-(Y)}= 693.08 barns/electron
U=PE_{Yttrialite-(Y)} x r_electron=2,850.86 barns/cc.

Radioactivity:

GRapi = 532,369.91 (Gamma Ray American Petroleum Institute Units)
Concentration of Yttrialite-(Y) per GRapi unit =1,878.39 (PPB)

Yttrialite-(Y) 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) 57.13 ± 14.28 grams of pure Yttrialite-(Y) .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 5713.4 ±1428.4 grams of pure Yttrialite-(Y) .

**Estimated Radioactivity from Yttrialite-(Y)** - strong
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 / 7.47 cm	12,448,139	3.36E-04	532,369.91	175.03
100 gm / 3.47 cm	1,244,814	3.36E-05	53,236.99	17.50
10 gm / 1.61 cm	124,481	3.36E-06	5,323.70	1.75
1 gm / 7.47 mm	12,448	3.36E-07	532.37	0.18
0.1 gm / 3.47 mm	1,245	3.36E-08	53.24	0.02
0.01 gm / 1.61 mm	124	3.36E-09	5.32	0.00
0.001 gm / 0.75 mm	12	3.36E-10	0.53	0.00

Weight of pure Yttrialite-(Y) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.58 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

Yttrialite-(Y) Classification

Dana Class:

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

(55.02)with cations in [6] coordination

(55.02.01b)Thortveitite related species

55.02.01b.01 Rowlandite-(Y) Y4FeSi4O14F2(?) None

55.02.01b.02 Thalenite-(Y) Y3Si3O10(OH) P 2₁/n 2/m

55.02.01b.03 Yttrialite-(Y) (Y,Th)2Si2O7 P 2₁/m 2/m

55.02.01b.04 Fluorthalenite-(Y)! Y3Si3O10F P 2₁/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 Yttrialite-(Y) Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Yttrialite-(Y) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

Search for Yttrialite-(Y) using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Yttrialite-(Y) :

Ask about Yttrialite-(Y) here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Yttrialite-(Y) Specimen Label here :

Yttrialite-(Y)

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

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.