Tombarthite-(Y) Mineral Data

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General Tombarthite-(Y) Information

Chemical Formula:

Y4(Si,H4)4O12-x(OH)4+2x

Composition:

Molecular Weight = 744.26 gm

Calcium 4.31 % Ca 6.03 % CaO

La,Ce,Pr,Nd,Sm, 19.35 % RE 22.57 % REE₂O₃

Yttrium 26.28 % Y 33.37 % Y₂O₃

Silicon 7.55 % Si 16.15 % SiO₂

Hydrogen 2.53 % H 22.63 % H₂O

Oxygen 39.98 % O

______ ______

100.00 % 100.75 % = TOTAL OXIDE

Empirical Formula:

Y_2.2REECa_0.8Si₂H_8.2O_8.1(OH)_10.5

Environment:

In pegmatite dikes cutting amphibolites.

IMA Status:

Approved IMA 1968

Locality:

Hogetveit quarry, near Setesdal, Evje, and at Reiarsdal, Norway. Link to MinDat.org Location Data.

Name Origin:

Named after Thomas Fredrik Barth (1899-1971), mineralogist and petroligist, Oslo University, Oslo, Norway.

Name Pronunciation:

Tombarthite-(Y) + Pronunciation

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Tombarthite-(Y) Crystallography

Axial Ratios:

a:b:c =0.9766:1:0.9204

Cell Dimensions:

a = 7.12, b = 7.29, c = 6.71, Z = 1; beta = 102.683° V = 339.78 Den(Calc)= 3.64

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/n

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

By Intensity(I/I_o): 6.55(1), 3.42(0.8), 3.23(0.7),

Physical Properties of Tombarthite-(Y)

Cleavage:

None

Color:

Brownish black.

Density:

3.51

Diaphaneity:

Translucent to opaque

Fracture:

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

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Metamict - Mineral originally crystalline, now amorphous due to radiation damage.

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Earthy (Dull)

Optical Properties of Tombarthite-(Y)

Gladstone-Dale:

CI meas= 0.13 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.161 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1755,KPDmeas= 0.1821,KC= 0.2093
Ncalc = 1.73 - 1.76

Optical Data:

Isotropic, n=1.639.

Calculated Properties of Tombarthite-(Y)

Electron Density:

Bulk Density (Electron Density)=3.38 gm/cc
note: Specific Gravity of Tombarthite-(Y) =3.51 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_{Tombarthite-(Y)}= 146.79 barns/electron
U=PE_{Tombarthite-(Y)} x r_electron= 496.09 barns/cc.

Radioactivity:

GRapi = 19,942.06 (Gamma Ray American Petroleum Institute Units)
Concentration of Tombarthite-(Y) per GRapi unit = 50.15 (PPM)

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

**Estimated Radioactivity from Tombarthite-(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 / 8.16 cm	434,950	1.18E-05	19,942.06	6.56
100 gm / 3.79 cm	43,495	1.18E-06	1,994.21	0.66
10 gm / 1.76 cm	4,350	1.18E-07	199.42	0.07
1 gm / 8.16 mm	435	1.18E-08	19.94	0.01
0.1 gm / 3.79 mm	43	1.18E-09	1.99	0.00
0.01 gm / 1.76 mm	4	1.18E-10	0.20	0.00
0.001 gm / 0.82 mm	0	1.18E-11	0.02	0.00

Weight of pure Tombarthite-(Y) in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.51 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 ( 0.97 % Th) From Sum REE Elements (19.35 % REE)

Tombarthite-(Y) Classification

Dana Class:

51.05.03.02 (51)Nesosilicate Insular SiO4 Groups Only

(51.05)with cations in >[6] coordination

(51.05.03)Huttonite group

51.05.03.01 Huttonite ThSiO4 P 2₁/n 2/m

51.05.03.02 Tombarthite-(Y) Y4(Si,H4)4O12-x(OH)42x P 2₁/n 2/m

Strunz Class:

09.AD.35 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AD -Nesosilicates without additional anions;

09.AD.35 Huttonite ThSiO4 P 2₁/n 2/m

09.AD.35 Tombarthite-(Y) Y4(Si,H4)4O12-x(OH)42x P 2₁/n 2/m

Other Tombarthite-(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 Tombarthite-(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

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

Tombarthite-(Y)

Y4(Si,H4)4O12-x(OH)4+2x
Dana No: 51.05.03.02 Strunz No: 09.AD.35
Locality:

Notes: