Foitite Mineral Data

Foitite Mineral Data +

General Foitite Information

Chemical Formula:

[ ]Na<0.5(Fe++,Al)3Al6Si6O18(BO3)3(OH)4

Composition:

Molecular Weight = 1,031.73 gm

Sodium 2.23 % Na 3.00 % Na₂O

Aluminum 17.65 % Al 33.35 % Al₂O₃

Iron 12.18 % Fe 17.41 % Fe₂O₃

Silicon 16.33 % Si 34.94 % SiO₂

Boron 3.14 % B 10.12 % B₂O₃

Hydrogen 0.39 % H 3.49 % H₂O

Oxygen 48.07 % O

______ ______

100.00 % 102.33 % = TOTAL OXIDE

Empirical Formula:

NaFe³⁺_2.25Al_6.75Si₆O₁₈(BO₃)₃(OH)₄

Environment:

Late-stage granitic pegmatite.

IMA Status:

Approved IMA 1993 (Dana # Changed)

Locality:

White Queen mine, Pala, San Diego County, California, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Ranklin F. Foit, Jr. (1942-), mineralogist, Washington State Univerisity, Washington, USA.

Synonym:

Foitite - (61.3.1.1)

ICSD 74012

IMA1992-034

PDF 46-1460

Tourmaline

Foitite Image

Images:

Foitite

Comments: Dark greenish-black termination of foitite on pinkish elbaite.
Location: Dobra Voda, Moravia, Zapadocesky, Czech Republic. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Foitite Crystallography

Axial Ratios:

a:c = 1:0.44629

Cell Dimensions:

a = 15.967, c = 7.126, Z = 3; V = 1,573.34 Den(Calc)= 3.27

Crystal System:

Trigonal - Ditrigonal PyramidalH-M Symbol (3m) Space Group: R 3m

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

By Intensity(I/I_o): 2.573(1), 3.452(0.91), 6.338(0.84),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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H - Help Screen
I - Data Info
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MacDonald D J , Hawthorne F C , Grice J D , American Mineralogist , 78 (1993) p.1299-1303

View Additional jPOWD Structure files for Foitite
[1] [2]

Physical Properties of Foitite

Cleavage:

None

Color:

Bluish black.

Density:

3.17

Diaphaniety:

Translucent to Opaque

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Striated - Parallel lines on crystal surface or cleavage face.

Hardness:

7 - Quartz

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

gray white

Optical Properties of Foitite

Dichroism (e):

dark blue.

Dichroism (w):

pale lavender.

Gladstone-Dale:

CI meas= 0.127 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.154 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1997,KPDmeas= 0.206,KC= 0.2359

Optical Data:

Uniaxial (-), e=1.642, w=1.664, bire=0.0220.

Calculated Properties of Foitite

Electron Density:

r_electron=3.12 gm/cc
note: r_Foitite=3.17 gm/cc.

Fermion Index

Fermion Index = 0.01669
Boson Index = 0.98331

Photoelectric:

PE_Foitite= 4.82 barns/electron
U=PE_Foitite x r_electron= 15.04 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Foitite is Not Radioactive

Foitite Classification

Dana Class:

61.3a.1.1 (61)Cyclosilicate Six-Membered Rings

(61.3a)with borate groups (Alkali-Deficient Tourmaline Subgroup)

(61.3a.1)Dana Group

61.3a.1.1 Foitite ! []Na<0.5(Fe,Al)3Al6Si6O18(BO3)3(OH)4 R 3m 3m

61.3a.1.2 Magnesiofoitite! [](Mg2Al)Al6(Si6O18)(BO3)3(OH)4 R 3m 3m

61.3a.1.3 Rossmanite! []LiAl2Al6(Si6O18)(BO3)3(OH)4 R 3m 3m

Strunz Class:

VIII/E.19-55 VIII - Silicates

VIII/E - Cyklosilicates, six rings [Si6O18]12-

VIII/E.19 - Tourmaline group

VIII/E.19-05 Rossmanite! []LiAl2Al6(Si6O18)(BO3)3(OH)4 R 3m 3m

VIII/E.19-10 Elbaite Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 R 3m 3m

VIII/E.19-15 Magnesiofoitite! [](Mg2Al)Al6(Si6O18)(BO3)3(OH)4 R 3m 3m

VIII/E.19-20 Dravite NaMg3Al6(BO3)3Si6O18(OH)4 R 3m 3m

VIII/E.19-30 Chromdravite! NaMg3(Cr,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m

VIII/E.19-35 Vanadiumdravite! NaMg3V6(Si6O18)(BO3)3(OH)4 R 3m 3m

VIII/E.19-50 Schorl NaFe3Al6(BO3)3Si6O18(OH)4 R 3m 3m

VIII/E.19-55 Foitite []Na<0.5(Fe,Al)3Al6Si6O18(BO3)3(OH)4 R 3m 3m

VIII/E.19-60 Olenite! NaAl3Al6(BO3)3(Si6O18)(O,OH)4 R 3m 3m

VIII/E.19-70 Buergerite! NaFe3Al6(BO3)3Si6O21F R 3m 3m

VIII/E.19-75 Povondraite! (Na,K)(Fe,Fe)3(Fe,Mg,Al)6(BO3)3Si6O18(OH)4 R 3m 3m

VIII/E.19-80 Liddicoatite! Ca(Li,Al)3Al6(BO3)3Si6O18(O,OH,F)4 R 3m 3m

VIII/E.19-90 Uvite (Ca,Na)(Mg,Fe)3Al5Mg(BO3)3Si6O18(OH,F)4 R 3m 3m

VIII/E.19-100 Feruvite! (Ca,Na)(Fe,Mg,Ti)3(Al,Mg,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m

Other Foitite Information

References:

NAME( Dana8) PHYS. PROP.(Am.Min.,78:1299) OPTIC PROP.(Am.Min.,Vol.78,p1299-1303,1993)

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Foitite

[ ]Na<0.5(Fe++,Al)3Al6Si6O18(BO3)3(OH)4
Dana No: 61.3a.1.1 Strunz No: VIII/E.19-55
Locality:

Notes: