Tornebohmite-(La) Mineral Data

General Tornebohmite-(La) Information

Chemical Formula: (La,Ce)2Al(SiO4)2(OH) Composition: Molecular Weight = 506.57 gm    Lanthanum  41.13 %  La   48.24 % La₂O₃    Cerium     13.83 %  Ce   16.20 % Ce₂O₃    Aluminum    5.33 %  Al   10.06 % Al₂O₃    Silicon    11.09 %  Si   23.72 % SiO₂    Hydrogen    0.20 %  H     1.78 % H₂O    Oxygen     28.43 %  O              ______        ______               100.00 %      100.00 % = TOTAL OXIDE Empirical Formula: La_1.5Ce_0.5Al(SiO₄)₂(OH) Environment: Rare-earth ore deposits. IMA Status: Valid Species (Pre-IMA) 1921 Locality: Bastnas mine, 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. Name Pronunciation: Tornebohmite-(La) + Pronunciation  

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Tornebohmite-(La) 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)= 5.12 Crystal System: Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/c X Ray Diffraction: By Intensity(I/I_o): 3.09(1), 2.82(0.7), 4.6(0.7),2.63(0.6), 2.18(0.4), 2.84(0.4), 3.48(0.4), 2(0.2),  

Physical Properties of Tornebohmite-(La)

Color: Green, Bright olive green. Density: 4.94 Hardness: 4.5 - Between Fluorite and Apatite Luster: Adamantine - Greasy  

Optical Properties of Tornebohmite-(La)

Gladstone-Dale: CI meas= 0.03 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.064 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.16,KPDmeas= 0.1659,KC= 0.1709
Ncalc = 1.84 - 1.88 Optical Data: Biaxial (+), a=1.808, b=1.812, g=1.838, bire=0.0300 Pleochroism (x): pink or greenish yellow. Pleochroism (y): bluish green or bluish green. Pleochroism (z): pink or pink.  

Calculated Properties of Tornebohmite-(La)

Electron Density: Bulk Density (Electron Density)=4.46 gm/cc
note: Specific Gravity of Tornebohmite-(La) =4.94 gm/cc.
Fermion Index: Fermion Index = 0.00568524
Boson Index = 0.99431476 Photoelectric: PE_{Tornebohmite-(La)} = 267.42 barns/electron
U=PE_{Tornebohmite-(La)} x r_electron=1,191.77 barns/cc.
Radioactivity:

GRapi = 52,888.17 (Gamma Ray American Petroleum Institute Units)
Concentration of Tornebohmite-(La) per GRapi unit = 18.91 (PPM)

Tornebohmite-(La) 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) 575.11 ±143.78 grams of pure Tornebohmite-(La) .

Estimated Radioactivity from Tornebohmite-(La) - weak

Specimen Size Weight/Volume (Sphere) *	Calculated Activity Becquerels (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 7.28 cm	1,231,124	3.33E-05	52,888.17	17.39
100 gm / 3.38 cm	123,112	3.33E-06	5,288.82	1.74
10 gm / 1.57 cm	12,311	3.33E-07	528.88	0.17
1 gm / 7.28 mm	1,231	3.33E-08	52.89	0.02
0.1 gm / 3.38 mm	123	3.33E-09	5.29	0.00
0.01 gm / 1.57 mm	12	3.33E-10	0.53	0.00
0.001 gm / 0.73 mm	1	3.33E-11	0.05	0.00

Weight of pure Tornebohmite-(La) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.94 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 ( 2.75 % Th) From Sum REE Elements (54.96 % REE)

 

Tornebohmite-(La) Classification

Dana Class: 52.04.05.02 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O   (52.04)with cations in [6] and/or > [6] coordination   (52.04.05)Tornebohmite group  

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

 

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

Strunz Class: 09.AG.45 09 - SILICATES (Germanates)   09.A - Nesosilicates   09.AG -Nesosilicates with additional anions; cations in > [6] ± [6] coordination  

09.AG.45 Tornebohmite-(Ce) (Ce,La,Nd)2Al(SiO4)2(OH) P 2₁/c 2/m

 

09.AG.45 Tornebohmite-(La) (La,Ce)2Al(SiO4)2(OH) P 2₁/c 2/m

 

Other Tornebohmite-(La) Information

References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8) See Also: Links to other databases for Tornebohmite-(La) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info
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