Tantalaeschynite-(Y) Mineral Data

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General Tantalaeschynite-(Y) Information

Chemical Formula:

(Y,Ce,Ca)(Ta,Ti,Nb)2O6

Composition:

Molecular Weight = 499.75 gm

Calcium 0.80 % Ca 1.12 % CaO

Cerium 8.41 % Ce 9.85 % Ce₂O₃

Yttrium 10.67 % Y 13.56 % Y₂O₃

Tantalum 54.31 % Ta 66.32 % Ta₂O₅

Titanium 2.87 % Ti 4.80 % TiO₂

Niobium 3.72 % Nb 5.32 % Nb₂O₅

Oxygen 19.21 % O

______ ______

100.00 % 100.96 % = TOTAL OXIDE

Empirical Formula:

Y_0.6Ce_0.3Ca_0.1Ta_1.5Ti_0.3Nb_0.2O₆

Environment:

In a pegmatite.

IMA Status:

Approved IMA 1974

Locality:

São Jose do Sabugí, Paraíba, Brazil. Link to MinDat.org Location Data.

Name Origin:

Named for its composition and from the Greek for "shame," in allusion to the inability of chemists, at the time of its discovery, to separate some of its constituents.

Name Pronunciation:

Tantalaeschynite-(Y) + Pronunciation

Synonym:

Tantal-aeschynite-(Y) - Renamed Tantalaeschynite-(Y) by Mineralogical Record, v39 (2008), p131

Tantalaeschynite-(Y) Image

Images:

Tantalaeschynite-(Y)

Comments: Nearly pure fragment of tantalaeschynite-(Y).
Location: Raposa Pegmatite, São José do Sabugi, Paraíba, Northeast Region, Brazil. Scale: Specimen Size 1 cm.
© Jeff Weissman / Photographic Guide to Mineral Species

Tantalaeschynite-(Y) Crystallography

Axial Ratios:

a:b:c =0.4867:1:0.6727

Cell Dimensions:

a = 5.34, b = 10.97, c = 7.38, Z = 4; V = 432.32 Den(Calc)= 7.68

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pbnm

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

By Intensity(I/I_o): 2.94(1), 3(1), 1.581(0.7),

Physical Properties of Tantalaeschynite-(Y)

Cleavage:

None

Color:

Brownish black, Black.

Density:

5.75 - 6.13, Average = 5.94

Diaphaneity:

Subtranslucent

Fracture:

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

Habit:

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

Hardness:

5.5-6 - Knife Blade-Orthoclase

Luminescence:

Radioactive.

Luster:

Resinous

Streak:

yellowish brown

Optical Properties of Tantalaeschynite-(Y)

Optical Data:

Isotropic.

NCalc= 2.33 - from Gladstone-Dale relationship (KC = 0.1728) where Ncalc=Dcalc*KC+1
NCalc= 2.03 - from Gladstone-Dale relationship (KC = 0.1728) where Ncalc=Dmeas*KC+1

RL Color:

Dark gray with abundant white to dark red internal reflections.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Tantalaeschynite-(Y) in Air**
λ	R	∑ R(λ)
470 nm	14.50
546 nm	14.20
589 nm	14.00
650 nm	14.00

**Calculated Relative Intensity Colors of Tantalaeschynite-(Y) in Air**
Relative Intensity	0%	70%	100%	140%	210%	280%	350%	420%	490%	560%	630%
R

Calculated Properties of Tantalaeschynite-(Y)

Electron Density:

Bulk Density (Electron Density)=6.61 gm/cc
note: Specific Gravity of Tantalaeschynite-(Y) =7.68 gm/cc.

Fermion Index:

Fermion Index = 0.0038845967
Boson Index = 0.9961154033

Photoelectric:

PE_{Tantalaeschynite-(Y)}= 716.11 barns/electron
U=PE_{Tantalaeschynite-(Y)} x r_electron=4,734.34 barns/cc.

Radioactivity:

GRapi = 7,723.26 (Gamma Ray American Petroleum Institute Units)
Concentration of Tantalaeschynite-(Y) per GRapi unit = 129.48 (PPM)

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

**Estimated Radioactivity from Tantalaeschynite-(Y)** - mild
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 / 6.29 cm	188,409	5.09E-06	7,723.26	2.54
100 gm / 2.92 cm	18,841	5.09E-07	772.33	0.25
10 gm / 1.35 cm	1,884	5.09E-08	77.23	0.03
1 gm / 6.29 mm	188	5.09E-09	7.72	0.00
0.1 gm / 2.92 mm	19	5.09E-10	0.77	0.00
0.01 gm / 1.35 mm	2	5.09E-11	0.08	0.00
0.001 gm / 0.63 mm	0	5.09E-12	0.01	0.00

Weight of pure Tantalaeschynite-(Y) in grams (gm) and Calculated Diameter of a Sphere with a Density of 7.68 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 ( 0.42 % Th) From Sum REE Elements ( 8.41 % REE)

Tantalaeschynite-(Y) Classification

Dana Class:

08.03.06.04 (08)Multiple Oxides with Nb, Ta, and Ti

(08.03)where A (B2O6)

(08.03.06)Aeschynite group

08.03.06.01 Aeschynite-(Ce) (Ce,Ca,Fe)(Ti,Nb)2(O,OH)6 Pmnb 2/m 2/m 2/m

08.03.06.02 Nioboaeschynite-(Ce) (Ce,Ca)(Nb,Ti)2(O,OH)6 Pbnm 2/m 2/m 2/m

08.03.06.03 Aeschynite-(Y) (Y,Ca,Fe)(Ti,Nb)2(O,OH)6 Pbnm 2/m 2/m 2/m

08.03.06.04 Tantalaeschynite-(Y) (Y,Ce,Ca)(Ta,Ti,Nb)2O6 Pbnm 2/m 2/m 2/m

08.03.06.05 Aeschynite-(Nd) (Nd,Ce)(Ti,Nb)2(O,OH)6 Pmnb ? 2/m 2/m 2/m

08.03.06.06 Nioboaeschynite-(Nd)! (Nd,Ce)(Nb,Ti)2(O,OH)6 Pbnm 2/m 2/m 2/m

08.03.06.07 Nioboaeschynite-(Y)! [(Y,REE),Ca,Th,Fe](Nb,Ti,Ta)2(O,OH)6 Pbnm 2/m 2/m 2/m

Strunz Class:

04.DF.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.D - Metal:Oxygen = 1:2 and similar

04.DF -With large (± medium-sized) cations; dimers and trimers of edge-sharing octahedra

04.DF.05 Aeschynite-(Ce) (Ce,Ca,Fe)(Ti,Nb)2(O,OH)6 Pmnb 2/m 2/m 2/m

04.DF.05 Aeschynite-(Nd) (Nd,Ce)(Ti,Nb)2(O,OH)6 Pmnb ? 2/m 2/m 2/m

04.DF.05 Aeschynite-(Y) (Y,Ca,Fe)(Ti,Nb)2(O,OH)6 Pbnm 2/m 2/m 2/m

04.DF.05 Nioboaeschynite-(Ce) (Ce,Ca)(Nb,Ti)2(O,OH)6 Pbnm 2/m 2/m 2/m

04.DF.05 Nioboaeschynite-(Nd)! (Nd,Ce)(Nb,Ti)2(O,OH)6 Pbnm 2/m 2/m 2/m

04.DF.05 Rynersonite Ca(Ta,Nb)2O6 Pmnb 2/m 2/m 2/m

04.DF.05 Tantalaeschynite-(Y) (Y,Ce,Ca)(Ta,Ti,Nb)2O6 Pbnm 2/m 2/m 2/m

04.DF.05 Vigezzite (Ca,Ce)(Nb,Ta,Ti)2O6 Pmnb 2/m 2/m 2/m

04.DF.05 Nioboaeschynite-(Y)! [(Y,REE),Ca,Th,Fe](Nb,Ti,Ta)2(O,OH)6 Pbnm 2/m 2/m 2/m

Other Tantalaeschynite-(Y) Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)

See Also:

Links to other databases for Tantalaeschynite-(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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Tantalaeschynite-(Y)

(Y,Ce,Ca)(Ta,Ti,Nb)2O6
Dana No: 08.03.06.04 Strunz No: 04.DF.05
Locality:

Notes: