Fersmanite Mineral Data

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.

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 - PrismaticH-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),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Sokolova E V , Hawthorne F C , Khomyakov A P , The Canadian Mineralogist , 40 (2002) p.1421-1428, The crystal chemistry of fersmanite, Ca4(Na,Ca)4(Ti,Nb)4(Si2O7)2O8F3

Physical Properties of Fersmanite

Cleavage:

None

Color:

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

Density:

3.44

Diaphaniety:

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

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:

r_electron=3.33 gm/cc
note: r_Fersmanite=3.44 gm/cc.

Fermion Index

Fermion Index = 0.01937
Boson Index = 0.98063

Photoelectric:

PE_Fersmanite= 26.13 barns/electron
U=PE_Fersmanite x r_electron= 87.01 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Fersmanite is Not Radioactive

Fersmanite Classification

Dana Class:

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

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

(56.2.5)Mosandrite and related species

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

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

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

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

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

Strunz Class:

VIII/C.16-30 VIII - Silicates

VIII/C - Sorosilicates with [Si2O7]6-, with anions unfamiliar to tetraheders [O,OH,F]

VIII/C.16 - Komarovite series

VIII/C.16-10 Na-komarovite? Na6CaNb6[Si4O12F2·4(H2O) C mmm 2/m 2/m 2/m

VIII/C.16-20 Komarovite (Ca,Mn)2(Nb,Ti)2Si2O7(O,F)2·3.5(H2O) Unk Ortho

VIII/C.16-30 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)

Search for Fersmanite using:

[ALTAVISTA] [AOL] [About.com] [All-The-Web] [HotBot] [Ixquick] [LookSmart] [MAMMA] [MSN.COM] [Netscape] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Fersmanite :
AA Mineral Specimens
A-Rocks Auction
Adams Minerals
B and L Minerals
Dakota Matrix
Dan Weinrich Fine Minerals
Dan Weinrich Auctions
e-Rocks Auctions
Excalibur Minerals
Exceptional Minerals
Fabre Minerals
Greenside Minerals
John Betts Fine Minerals
Masons Minerals
Mineral News
Mineral of the Month Club
MineralsWeb Fine Minerals
Minernet.it
Rockshop.cz Kalat Fine Minerals
T G Fine Minerals
Wrights Rock Shop

Translate Fersmanite Mineral Data :

Ask about Fersmanite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Fersmanite

Ca4(Na,Ca)4(Ti,Nb)4(Si2O7)2O8F3
Dana No: 56.2.5.3 Strunz No: VIII/C.16-30
Locality:

Notes: