Seidite-(Ce) Mineral Data

General Seidite-(Ce) Information

Chemical Formula:

Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4•5(H2O)

Composition:

Molecular Weight = 1,096.99 gm

Sodium 8.38 % Na 11.30 % Na₂O

Strontium 3.99 % Sr 4.72 % SrO

Cerium 19.16 % Ce 22.44 % Ce₂O₃

Titanium 4.36 % Ti 7.28 % TiO₂

Silicon 20.48 % Si 43.82 % SiO₂

Hydrogen 1.21 % H 10.84 % H₂O

Oxygen 41.71 % O

Fluorine 0.69 % F 0.69 % F

- % F -0.29 % -O=F₂

______ ______

100.00 % 100.80 % = TOTAL OXIDE

Empirical Formula:

Na₄Ce_1.5Sr_0.5Ti(OH)₂Si₈O₁₈O_2.4(OH)_1.2F_0.4ï¿½5(H₂O)

Environment:

In cavernous natrolite in the Jubileinaya hyperagpaitic pegmatites. Na cations are exchangable indicating a micro-porous structure.

IMA Status:

Approved IMA 1997 (Dana # Added)

Locality:

Found at Mount Karnasurt, Lovozero alkaline complex, Kola Peninsula, Russia. Link to MinDat.org Location Data.

Name Origin:

Named after Seidozero, literally Lake Seid, the central lake in the Lovozero complex.

Synonym:

IMA1993-029

Seidite-(Ce) Image

Images:

Seidite-(Ce)

Comments: Scanning Electron image of seidite-(Ce) with the axial components of a and c superimposed on crystal.
Location: Yubileynaya pegmatite at Mount Karnasurt, Lovozero alkaline massif, Kola Peninsula, Russia. Scale: Image size 0.5 mm.
© Canadian Mineralogist

Seidite-(Ce) Crystallography

Axial Ratios:

a:b:c =3.4038:1:2.0096

Cell Dimensions:

a = 24.61, b = 7.23, c = 14.53, Z = 4; beta = 94.6° V = 2,577.00 Den(Calc)= 2.83

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C/2c

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

By Intensity(I/I_o): 12.32(1), 3.22(0.86), 3.108(0.29),3.14(0.24), 3.081(0.16), 3.058(0.12),

Physical Properties of Seidite-(Ce)

Cleavage:

{100} Perfect, {001} Very Good

Color:

Yellow, Pinkish yellow, Cream.

Density:

2.76

Diaphaneity:

Translucent

Fracture:

Brittle - Splintery - Brittle fracture leaving splintery fragments.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Hardness:

3-4 - Calcite-Fluorite

Luster:

Vitreous - Silky

Streak:

white

Optical Properties of Seidite-(Ce)

Gladstone-Dale:

CI meas= 0.066 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.089 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1981,KPDmeas= 0.2031,KC= 0.2176
Ncalc = 1.6 - 1.62

Optical Data:

Biaxial (-), a=1.542, b=1.569, g=1.571, bire=0.0290

Calculated Properties of Seidite-(Ce)

Electron Density:

Bulk Density (Electron Density)=2.66 gm/cc
note: Specific Gravity of Seidite-(Ce) =2.76 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Seidite-(Ce)= 97.68 barns/electron
U=PE_Seidite-(Ce) x r_electron= 260.32 barns/cc.

Radioactivity:

GRapi = 19,732.19 (Gamma Ray American Petroleum Institute Units)
Concentration of Seidite-(Ce) per GRapi unit = 50.68 (PPM)

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

**Estimated Radioactivity from Seidite-(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 / 8.84 cm	429,161	1.16E-05	19,732.19	6.49
100 gm / 4.11 cm	42,916	1.16E-06	1,973.22	0.65
10 gm / 1.91 cm	4,292	1.16E-07	197.32	0.06
1 gm / 8.84 mm	429	1.16E-08	19.73	0.01
0.1 gm / 4.11 mm	43	1.16E-09	1.97	0.00
0.01 gm / 1.91 mm	4	1.16E-10	0.20	0.00
0.001 gm / 0.88 mm	0	1.16E-11	0.02	0.00

Weight of pure Seidite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 2.76 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 ( 0.96 % Th) From Sum REE Elements (19.16 % REE)

Seidite-(Ce) Classification

Dana Class:

72.05.01.06 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings

(72.05)with corrugated and complex layers

(72.05.01)Rhodesite group

72.05.01.01 Rhodesite KHCa2Si8O19•5(H2O) Pmam 2/m 2/m 2/m

72.05.01.02 Monteregianite-(Y) (Na,K)6(Y,Ca)2Si16O38•10(H2O) P 2₁/m 2/m

72.05.01.03 Macdonaldite BaCa4[Si16O36(OH)2]•10(H2O) C mcm 2/m 2/m 2/m

72.05.01.04 Delhayelite (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O) Pnmm 2/m 2/m 2/m

72.05.01.05 Hydrodelhayelite KCa2AlSi7O17(OH)2•6(H2O) Pnm21 mm2

72.05.01.06 Seidite-(Ce)! Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4•5(H2O) C/2c 2/m

Strunz Class:

09.DJ.20 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DJ -Inosilicates with 4-periodic double and triple chains

09.DJ.20 Seidite-(Ce)! Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4•5(H2O) C/2c 2/m

Other Seidite-(Ce) Information

References:

NAME( CanMin, 8/99) PHYS. PROP.(MinRec, v 31, No. 2, CanMin, v 41, p 1183) OPTIC PROP.(MinRec, V 31, No. 2)

See Also:

Links to other databases for Seidite-(Ce) :
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

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Seidite-(Ce)

Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4•5(H2O)
Dana No: 72.05.01.06 Strunz No: 09.DJ.20
Locality:

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