Tornebohmite-(Ce) Mineral Data

Tornebohmite-(Ce) Mineral Data +

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General Tornebohmite-(Ce) Information

Chemical Formula:

(Ce,La,Nd)2Al(SiO4)2(OH)

Composition:

Molecular Weight = 509.02 gm

Lanthanum 13.64 % La 16.00 % La₂O₃

Cerium 33.03 % Ce 38.69 % Ce₂O₃

Aluminum 5.30 % Al 10.02 % Al₂O₃

Silicon 11.04 % Si 23.61 % SiO₂

Hydrogen 0.20 % H 1.77 % H₂O

Neodymium 8.50 % Nd 9.92 % Nd₂O₃

Oxygen 28.29 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ce_1.2La_0.5Nd_0.3Al(SiO₄)₂(OH)

Environment:

Rare-earth ore deposits.

IMA Status:

Valid Species (Pre-IMA) 1921

Locality:

Bastnaes mine near Riddarhyttan, Vastmanland, Sweden. Link to MinDat.org Location Data.

Name Origin:

Named for Alfred Ellis Tornebohm (1839-1911), former director of the Geological Survey of Sweden.

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Tornebohmite-(Ce) Crystallography

Axial Ratios:

a:b:c =1.3014:1:2.9855

Cell Dimensions:

a = 7.383, b = 5.673, c = 16.937, Z = 4; beta = 112.04° V = 657.54 Den(Calc)= 5.14

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): 3.08(1), 2.82(0.9), 2.01(0.6),

Crystal Structure:

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Shen J , Moore P B , American Mineralogist , 67 (1982) p.1021-1028, Tornebohmite, RE2Al(OH)[SiO4]2: Crystal structure and genealogy of, RE(III)Si(IV) <---> Ca(II)P(V) isomorphisms

Physical Properties of Tornebohmite-(Ce)

Color:

Green, Green.

Density:

4.9

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous - Adamantine

Optical Properties of Tornebohmite-(Ce)

Gladstone-Dale:

CI meas= -0.038 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.011 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.167,KPDmeas= 0.1752,KC= 0.1688

Optical Data:

Biaxial (+), a=1.845, b=1.852, g=1.878, bire=0.0330, 2V(Calc)=56, 2V(Meas)=26. Dispersion strong, r < v.

Pleochroism (x):

rose.

Pleochroism (y):

rose.

Pleochroism (z):

bluish green.

Calculated Properties of Tornebohmite-(Ce)

Electron Density:

r_electron=4.65 gm/cc
note: r_{Tornebohmite-(Ce)}=5.14 gm/cc.

Fermion Index

Fermion Index = 0.02282
Boson Index = 0.97718

Photoelectric:

PE_{Tornebohmite-(Ce)}= 283.48 barns/electron
U=PE_{Tornebohmite-(Ce)} x r_electron=1,317.34 barns/cc.

Radioactivity:

GRapi = 53,211.21 (Gamma Ray American Petroleum Institute Units)

Tornebohmite-(Ce) 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) 571.62 ±142.91 grams of pure Tornebohmite-(Ce) .

**Estimated Radioactivity from Tornebohmite-(Ce)** - 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 / 7.19 cm	1,235,973	3.34E-05	53,211.21	17.49
100 gm / 3.34 cm	123,597	3.34E-06	5,321.12	1.75
10 gm / 1.55 cm	12,360	3.34E-07	532.11	0.17
1 gm / 7.19 mm	1,236	3.34E-08	53.21	0.02
0.1 gm / 3.34 mm	124	3.34E-09	5.32	0.00
0.01 gm / 1.55 mm	12	3.34E-10	0.53	0.00
0.001 gm / 0.72 mm	1	3.34E-11	0.05	0.00

Weight of pure Tornebohmite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 5.14 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 ( 2.76 % Th) From Sum REE Elements (55.18 % REE)

Tornebohmite-(Ce) Classification

Dana Class:

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

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

(52.4.5)Tornebohmite group

52.4.5.1 Tornebohmite-(Ce) (Ce,La,Nd)2Al(SiO4)2(OH) P 2₁/c 2/m

52.4.5.2 Tornebohmite-(La) (La,Ce)2Al(SiO4)2(OH) P 2₁/c 2/m

Strunz Class:

VIII/B.19-20 VIII - Silicates

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

VIII/B.19 - Kuliokite-(Y) - Cerite-(Ce) series

VIII/B.19-10 Kuliokite-(Y) (Y,REE)4Al(SiO4)2(OH)2F5 P1 1

VIII/B.19-20 Tornebohmite-(Ce) (Ce,La,Nd)2Al(SiO4)2(OH) P 2₁/c 2/m

VIII/B.19-30 Tornebohmite-(La) (La,Ce)2Al(SiO4)2(OH) P 2₁/c 2/m

VIII/B.19-40 Cerite-(Ce) Ce9Fe(SiO4)6[(SiO3)(OH)](OH)3 R 3c 3m

VIII/B.19-50 Cerite-(La)! (La,Ce,Ca)9(Mg,Fe)(SiO4)6[SiO3(OH)](OH)3 R 3c 3m

Other Tornebohmite-(Ce) Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Tornebohmite-(Ce) :
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 13 - WWW-MINCRYST

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Tornebohmite-(Ce)

(Ce,La,Nd)2Al(SiO4)2(OH)
Dana No: 52.4.5.1 Strunz No: VIII/B.19-20
Locality:

Notes: