Semenovite Mineral Data

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General Semenovite Information

Chemical Formula:

(Na,Ca)9(Ce,La)2(Fe++,Mn)(Si,Be)20(O,OH,F)48

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

Empirical Formula:

Na_6.74Ca_2.04K_0.04La_0.8Ce_0.74Y_0.32REE_0.44Mn²⁺_0.48Fe²⁺_0.21Zn_0.12Pb_0.04Fe³⁺_0.57Si_13.55 Be_6.24Al_0.26O_40.4F_4.51(OH)_4.04

Environment:

Occurs in border zone of the only epididymite-eudidymite bearing albitite, in cavities and fractures.

IMA Status:

Approved IMA 1972

Locality:

Ilimaussaq complex, South Greenland. Link to MinDat.org Location Data.

Name Origin:

Named for Yevgeny Ivanovich Semenov, (1951-), Russian mineralogist, IMGRE, Moscow, Russia.

Name Pronunciation:

Semenovite + Pronunciation

Semenovite Image

Images:

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

Axial Ratios:

a:b:c =1.0031:1:0.7186

Cell Dimensions:

a = 13.879, b = 13.835, c = 9.942, Z = 2; V = 1,909.02 Den(Calc)= 3.26

Crystal System:

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

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

By Intensity(I/I_o): 2.73(1), 2.84(1), 3.28(1),

Crystal Structure:

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Mazzi F , Ungaretti L , Dal Negro A , Petersen O V , Ronsbo J G , American Mineralogist , 64 (1979) p.202-210, The crystal structure of semenovite

Physical Properties of Semenovite

Cleavage:

None

Color:

Brown, Orange brown, Gray, Reddish brown, Colorless.

Density:

3.14

Diaphaneity:

Transparent to translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Pseudo Tetragonal - Crystals show a tetragonal shape.

Habit:

Twinning Common - Crystals are usually twinned.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Semenovite

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

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

Electron Density:

Bulk Density (Electron Density)=3.02 gm/cc
note: Specific Gravity of Semenovite =3.14 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Semenovite= 84.76 barns/electron
U=PE_Semenovite x r_electron= 255.67 barns/cc.

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

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

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

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

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: