Fersmanite Mineral Data

General Fersmanite Information

Chemical Formula:

Ca4(Na,Ca)4(Ti,Nb)4(Si2O7)2O8F3

Composition:

Molecular Weight = 1,061.05 gm

Sodium 5.63 % Na 7.59 % Na₂O

Strontium 0.83 % Sr 0.98 % SrO

Calcium 20.02 % Ca 28.01 % CaO

Titanium 10.38 % Ti 17.32 % TiO₂

Niobium 14.01 % Nb 20.04 % Nb₂O₅

Silicon 10.59 % Si 22.65 % SiO₂

Oxygen 33.17 % O

Fluorine 5.37 % F 5.37 % F

- % F -2.26 % -O=F₂

______ ______

100.00 % 99.70 % = TOTAL OXIDE

Empirical Formula:

Ca_5.3Na_2.6Sr_0.1Ti_2.3Nb_1.6Si₄O₂₂F₃

Environment:

Associated with feldspar and aegirite in veins in nepheline-syenite.

IMA Status:

Valid Species (Pre-IMA) 1929

Locality:

Chibines Mountains, Kola peninsula, Russia. Link to MinDat.org Location Data.

Name Origin:

Named for Alexander Yevgenievich Fersman (1883-1945), Russian mineralogist and geochemist.

Name Pronunciation:

Fersmanite + Pronunciation

Synonym:

ICSD 20821

PDF 29-1446

Fersmanite Image

Images:

Fersmanite

Comments: Large single crystal of brown fersmanite in quartz matrix.
Location: Khibiny Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia. Scale: 4x3x2 cm.
© John Betts - Fine Minerals

Fersmanite Crystallography

Axial Ratios:

a:b:c =1:1:2.0029

Cell Dimensions:

a = 10.183, b = 10.183, c = 20.396, Z = 4; beta = 97.19° V = 2,098.30 Den(Calc)= 3.36

Crystal System:

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

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

By Intensity(I/I_o): 3.058(1), 2.815(0.62), 1.518(0.55),

Physical Properties of Fersmanite

Cleavage:

None

Color:

Golden yellow, Resin brown, Light brown, Dark brown.

Density:

3.44

Diaphaneity:

Transparent to translucent

Fracture:

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

Habit:

Pseudo Tetragonal - Crystals show a tetragonal shape.

Hardness:

5.5 - Knife Blade

Luster:

Vitreous (Glassy)

Streak:

brownish white

Optical Properties of Fersmanite

Gladstone-Dale:

CI meas= -0.074 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= -0.1 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2706,KPDmeas= 0.2643,KC= 0.2461
Ncalc = 1.83 - 1.85

Optical Data:

Biaxial (-), a=1.873-1.886, b=1.914-1.93, g=1.914-1.939, bire=0.0410-0.0530, 2V(Calc)=0-46, 2V(Meas)=0-7.

Calculated Properties of Fersmanite

Electron Density:

Bulk Density (Electron Density)=3.33 gm/cc
note: Specific Gravity of Fersmanite =3.44 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Fersmanite= 26.13 barns/electron
U=PE_Fersmanite x rElectron Density= 87.01 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Fersmanite is Not Radioactive

Fersmanite Classification

Dana Class:

56.02.05.03 (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O

(56.02)with cations in [4] and/or >[4] coordination

(56.02.05)Mosandrite and related species

56.02.05.01 Mosandrite Na(Na,Ca)2(Ca,Ce,Y)4(Ti,Nb,Zr)(Si2O7)2(O,F)2F3 P 2₁ 2

56.02.05.02 Nacareniobsite-(Ce) NbNa3Ca3(Ce,La)(Si2O7)2OF3 P 2₁/a 2/m

56.02.05.03 Fersmanite Ca4(Na,Ca)4(Ti,Nb)4(Si2O7)2O8F3 C 2/c 2/m

56.02.05.04 Gotzenite (Ca,Na)3(Ti,Al)Si2O7(F,OH)2 P1 1

56.02.05.05 Rinkite! Na(Na,Ca)2(Ca,Ce)4(Ti,Nb)(Si2O7)2(O,F)2 P 2₁ 2

56.02.05.06 IMA2008-024! (Ca,Na,REE,[])7(Nb,Ti)[Si2O7]2OF3 Cc m

56.02.05.07 Dovyrenite! Ca6Zr[Si2O7]2(OH)4 Pnnm 2/m 2/m 2/m

Strunz Class:

09.BE.72 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BE -Si2O7 groups with additional anions;

09.BE.72 Fersmanite Ca4(Na,Ca)4(Ti,Nb)4(Si2O7)2O8F3 C 2/c 2/m

Other Fersmanite Information

References:

NAME( Ford32) PHYS. PROP.(Dana8, AmMin, v 88, p 1179) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Fersmanite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Fersmanite

Ca4(Na,Ca)4(Ti,Nb)4(Si2O7)2O8F3
Dana No: 56.02.05.03 Strunz No: 09.BE.72
Locality:

Notes:

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