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Semenovite Mineral Data

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General Semenovite Information

Help on Chemical  Formula: Chemical Formula: (Na,Ca)9(Ce,La)2(Fe++,Mn)(Si,Be)20(O,OH,F)48
Help on Composition: Composition: Molecular Weight = 1,875.54 gm
   Potassium         0.08 %  K     0.10 % K2O
   Sodium            8.26 %  Na   11.14 % Na2O
   Calcium           4.36 %  Ca    6.10 % CaO
   Lanthanum         5.92 %  La    6.95 % La2O3
   Cerium            5.53 %  Ce    6.48 % Ce2O3
   La,Ce,Pr,Nd,Sm,   3.38 %  RE    3.94 % REE2O3
   Yttrium           1.52 %  Y     1.93 % Y2O3
   Manganese         1.41 %  Mn    1.82 % MnO
   Beryllium         3.00 %  Be    8.32 % BeO
   Aluminum          0.37 %  Al    0.71 % Al2O3
   Zinc              0.42 %  Zn    0.52 % ZnO
   Iron              2.32 %   Fe    0.80 % FeO /  2.43 % Fe2O3
   Silicon          20.29 %  Si   43.41 % SiO2
   Hydrogen          0.22 %  H     1.94 % H2O
   Lead              0.44 %  Pb    0.48 % PbO
   Oxygen           37.91 %  O
   Fluorine          4.57 %  F     4.57 % F
                      -   %   F    -1.92 % -O=F2    
                   ______        ______ 
                   100.00 %       99.69 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na6.74Ca2.04K0.04La0.8Ce0.74Y0.32REE0.44Mn2+0.48Fe2+0.21Zn0.12Pb0.04Fe3+0.57Si13.55 Be6.24Al0.26O40.4F4.51(OH)4.04
Help on Environment: Environment: Occurs in border zone of the only epididymite-eudidymite bearing albitite, in cavities and fractures.
Help on IMA Status: IMA Status: Approved IMA 1972
Help on Locality: Locality: Ilimaussaq complex, South Greenland. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Yevgeny Ivanovich Semenov, (1951-), Russian mineralogist, IMGRE, Moscow, Russia.
Help on Name Pronunciation: Name Pronunciation: Semenovite + Pronunciation Say SEMENOVITE
 

Semenovite Image

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  Semenovite

Comments: Tan crystals of semenovite to 1 mm across on matrix.
Location: Ilimaussaq, Tasseq, Greenland. Scale: Picture size 1 cm.
© John Veevaert

Semenovite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.0031:1:0.7186
Help on Cell Dimensions: Cell Dimensions: a = 13.879, b = 13.835, c = 9.942, Z = 2; V = 1,909.02 Den(Calc)= 3.26
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pmmn
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.73(1), 2.84(1), 3.28(1),
 

Physical Properties of Semenovite

Help on Cleavage: Cleavage: None
Help on Color: Color: Brown, Orange brown, Gray, Reddish brown, Colorless.
Help on Density: Density: 3.14
Help on Diaphaneity: Diaphaneity: Transparent to translucent
Help on Fracture: Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Help on Habit: Habit: Pseudo Tetragonal - Crystals show a tetragonal shape.
Help on Habit: Habit: Twinning Common - Crystals are usually twinned.
Help on Hardness: Hardness: 3.5-4 - Copper Penny-Fluorite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white
 

Optical Properties of Semenovite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.017 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.053 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1864,KPDmeas= 0.1935,KC= 0.1968
Ncalc = 1.62 - 1.64
Help on Optical Data: Optical Data: Biaxial (-), a=1.595, b=1.614, g=1.614, bire=0.0190, 2V(Calc)=0, 2V(Meas)=0-55.
 

Calculated Properties of Semenovite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.02 gm/cc
note: Specific Gravity of Semenovite =3.14 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.04
Boson Index = 0.96
Help on Photoelectric: Photoelectric: PESemenovite = 84.76 barns/electron
U=PESemenovite x relectron= 255.67 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 15,211.68 (Gamma Ray American Petroleum Institute Units)
Concentration of Semenovite per GRapi unit = 65.74 (PPM)

Semenovite is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

Estimated Radioactivity from Semenovite - 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 / 8.47 cm 332,522 8.99E-06 15,211.68 5.00
100 gm / 3.93 cm 33,252 8.99E-07 1,521.17 0.50
10 gm / 1.83 cm 3,325 8.99E-08 152.12 0.05
1 gm / 8.47 mm 333 8.99E-09 15.21 0.01
0.1 gm / 3.93 mm 33 8.99E-10 1.52 0.00
0.01 gm / 1.83 mm 3 8.99E-11 0.15 0.00
0.001 gm / 0.85 mm 0 8.99E-12 0.02 0.00

Weight of pure Semenovite in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.14 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 ( 0.74 % Th) From Sum REE Elements (14.83 % REE)
 

Semenovite Classification

Help on  Dana Class: Dana Class: 72.05.02.04 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
  (72.05)with corrugated and complex layers
  (72.05.02)Leucospenite and related species
 
72.05.02.01 Leucosphenite Na4BaTi2O2[B2Si10O28] C 2/m 2/m
 
72.05.02.02 Nordite-(Ce) (Ce,La,Ca)(Sr,Ca)Na2(Na,Mn)(Zn,Mg)Si6O17 Pcca 2/m 2/m 2/m
 
72.05.02.03 Nordite-(La) (Na,Mn)3(Sr,Ca)(La,Ce)(Zn,Mg)Si6O17 Pcca 2/m 2/m 2/m
 
72.05.02.04 Semenovite (Na,Ca)9(Ce,La)2(Fe,Mn)(Si,Be)20(O,OH,F)48 Pmmn 2/m 2/m 2/m
 
72.05.02.05 Ferronordite-(Ce)! Na3SrCeFeSi6O17 Pcca 2/m 2/m 2/m
 
72.05.02.06 Manganonordite-(Ce)! Na3SrCeMnSi6O17 Pcca 2/m 2/m 2/m
 
72.05.02.07 Ferronordite-(La)! Na3Sr(La,Ce)FeSi6O17 Pcca 2/m 2/m 2/m
 
72.05.02.08 Bussyite-(Ce)! (Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4 C 2/c 2/m
Help on  Strunz Class: Strunz Class: 09.DN.10 09 - SILICATES (Germanates)
  09.D - Inosilicates* Structural terminology according to Liebau (1985)
  09.DN -Inosilicates with 6-periodic double chains
 
09.DN.10 Semenovite (Na,Ca)9(Ce,La)2(Fe,Mn)(Si,Be)20(O,OH,F)48 Pmmn 2/m 2/m 2/m
 

Other Semenovite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Semenovite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info
11 - WWW-MINCRYST

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Print or Cut-and-Paste your Semenovite Specimen Label here :

Semenovite

(Na,Ca)9(Ce,La)2(Fe++,Mn)(Si,Be)20(O,OH,F)48
Dana No: 72.05.02.04 Strunz No: 09.DN.10
Locality:

 

Notes:

 

 
   
 


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