Trimounsite-(Y) Mineral Data

Trimounsite-(Y) Mineral Data +

General Trimounsite-(Y) Information

Chemical Formula:

(Y,REE)2Ti2SiO9

Composition:

Molecular Weight = 475.18 gm

La,Ce,Pr,Nd,Sm, 15.15 % RE 17.68 % REE₂O₃

Yttrium 28.06 % Y 35.64 % Y₂O₃

Titanium 21.16 % Ti 35.30 % TiO₂

Silicon 5.32 % Si 11.38 % SiO₂

Oxygen 30.30 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Y_1.5REE_0.5Ti_2.1Si_0.9O₉

Environment:

In the dolomite portions of a talc deposit.

IMA Status:

Approved IMA 1990

Locality:

Trimouns talc deposit, 6 km northeast of Luzenac, Ariege, France. Link to MinDat.org Location Data.

Name Origin:

Named for the locality and the yttrium content.

Synonym:

IMA1989-042

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Trimounsite-(Y) Crystallography

Axial Ratios:

a:b:c =1.106:1:0.4368

Cell Dimensions:

a = 12.299, b = 11.12, c = 4.858, Z = 4; beta = 95.62° V = 661.21 Den(Calc)= 4.77

Crystal System:

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

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

By Intensity(I/I_o): 2.82(1), 3.44(0.9), 2.117(0.5),

Crystal Structure:

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Kolitsch U , European Journal of Mineralogy , 13 (2001) p.761-768, The crystal structure of trimounsite-(Y), (Y,REE)2Ti2SiO9:, an unusual TiO6-based titanate chain

Physical Properties of Trimounsite-(Y)

Color:

Light brown.

Density:

Diaphaniety:

Transparent to Translucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Striated - Parallel lines on crystal surface or cleavage face.

Hardness:

7 - Quartz

Luster:

Adamantine

Streak:

white

Optical Properties of Trimounsite-(Y)

Gladstone-Dale:

CI meas= 0.106 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.063 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2306,KPDmeas= 0.22,KC= 0.246

Optical Data:

Biaxial (-), a=2.1

Calculated Properties of Trimounsite-(Y)

Electron Density:

r_electron=4.41 gm/cc
note: r_{Trimounsite-(Y)}=4.77 gm/cc.

Fermion Index

Fermion Index = 0.05818
Boson Index = 0.94182

Photoelectric:

PE_{Trimounsite-(Y)}= 132.24 barns/electron
U=PE_{Trimounsite-(Y)} x r_electron= 583.54 barns/cc.

Radioactivity:

GRapi = 15,005.90 (Gamma Ray American Petroleum Institute Units)

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

**Estimated Radioactivity from Trimounsite-(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 / 7.37 cm	340,628	9.21E-06	15,005.90	4.93
100 gm / 3.42 cm	34,063	9.21E-07	1,500.59	0.49
10 gm / 1.59 cm	3,406	9.21E-08	150.06	0.05
1 gm / 7.37 mm	341	9.21E-09	15.01	0.00
0.1 gm / 3.42 mm	34	9.21E-10	1.50	0.00
0.01 gm / 1.59 mm	3	9.21E-11	0.15	0.00
0.001 gm / 0.74 mm	0	9.21E-12	0.02	0.00

Weight of pure Trimounsite-(Y) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.77 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 ( 0.76 % Th) From Sum REE Elements (15.15 % REE)

Trimounsite-(Y) Classification

Dana Class:

52.4.8.1 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.4)with cations in [6] and/or > [6] coordination

(52.4.8)Dana Group

52.4.8.1 Trimounsite-(Y) (Y,REE)2Ti2SiO9 P 2₁/c 2/m

Strunz Class:

VIII/B.12-30 VIII - Silicates

VIII/B - Nesosubsilicates, with anions unfamiliar to tetraheders, cationes with coordinationnumber between [8] and [12]

VIII/B.12 - Titanite series

VIII/B.12-10 Titanite CaTiSiO5 P 2₁/a 2/m

VIII/B.12-15 Vanadomalayaite CaVOSiO4 C 2/c 2/m

VIII/B.12-20 Malayaite CaSnSiO5=CaSnOSiO4 A2/a 2/m

VIII/B.12-30 Trimounsite-(Y) (Y,REE)2Ti2SiO9 P 2₁/c 2/m

Other Trimounsite-(Y) Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Am.Min.,Vol.76,p2024,1991) OPTIC PROP.(AntBidBlaNic2)

See Also:

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

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

Trimounsite-(Y)

(Y,REE)2Ti2SiO9
Dana No: 52.4.8.1 Strunz No: VIII/B.12-30
Locality:

Notes: