Magnesiofoitite Mineral Data

Magnesiofoitite Mineral Data

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General Magnesiofoitite Information

Chemical Formula:

[ ](Mg2Al)Al6(Si6O18)(BO3)3(OH)4

Composition:

Molecular Weight = 937.08 gm

Magnesium 3.89 % Mg 6.45 % MgO

Aluminum 21.31 % Al 40.26 % Al₂O₃

Silicon 17.98 % Si 38.47 % SiO₂

Boron 3.46 % B 11.14 % B₂O₃

Hydrogen 0.43 % H 3.84 % H₂O

Oxygen 52.93 % O

______ ______

100.00 % 100.17 % = TOTAL OXIDE

Empirical Formula:

Mg_1.5Al_7.4Si₆O₁₈(BO₃)₃(OH)₄

Environment:

Found in a hydrothermally altered quartz-phenocryst-bearing porphyry. The Mg analogue of foitite.

IMA Status:

Approved IMA 2001 (Dana # Added)

Locality:

Kyonosawa, Mitomi-mura, Higashi-Yamanashi-gun, Yamanashi-ken Prefecture, Honshu, Japan. Link to MinDat.org Location Data.

Name Origin:

The name recalls its composition and relationship to foitite.

Synonym:

IMA1998-037

Magnesiofoitite Image

Images:

Magnesiofoitite

Comments: Aggregate of greenish-brown acicular crystals of magnesiofoitite.
Location: Kyonosawa, Mitomi-mura, Yamanashi prefecture, Chubu region, Honshu island, Japan. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Magnesiofoitite Crystallography

Axial Ratios:

a:c = 1:0.4519

Cell Dimensions:

a = 15.884, c = 7.178, Z = 3; V = 1,568.39 Den(Calc)= 2.98

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): 2.567(1)(051), 3.969(1)(220), 4.211(0.9)(211),2.949(0.7)(122), 3.47(0.6)(012), 6.366(0.6)(101), 2.037(0.5)(152),

Physical Properties of Magnesiofoitite

Cleavage:

None

Color:

Pale bluish gray.

Diaphaniety:

Transparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Felted - Occurs as minute crystalling aggregates with the form of felt material.

Habit:

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

Hardness:

7 - Quartz

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Magnesiofoitite

Gladstone-Dale:

CI calc= -0.002 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2138,KC= 0.2133

Optical Data:

Uniaxial (-), e=1.624, w=1.65, bire=0.0260.

Calculated Properties of Magnesiofoitite

Electron Density:

r_electron=2.96 gm/cc
note: r_{Magnesiofoitite}=2.98 gm/cc.

Fermion Index

Fermion Index = 0.01943
Boson Index = 0.98057

Photoelectric:

PE_{Magnesiofoitite}= 1.45 barns/electron
U=PE_{Magnesiofoitite} x r_electron= 4.28 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Magnesiofoitite is Not Radioactive

Magnesiofoitite Classification

Dana Class:

61.3a.1.2 (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.19-15 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 Magnesiofoitite Information

References:

NAME( CanMin) PHYS. PROP.(AmMin, Vol 85, p 1562) OPTIC PROP.(AmMin, Vol 85, p 1562)

See Also:

Links to other databases for Magnesiofoitite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - Crocoite.com Mineral Locations 4 -Google Images 5 -Google Scholar 6 -MinDAT 7 -MinMax(Deutsch) 8 -MinMax(English) 9 -Mineralienatlas (Deutsch) 10 -QUT Mineral Atlas

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Magnesiofoitite

[ ](Mg2Al)Al6(Si6O18)(BO3)3(OH)4
Dana No: 61.3a.1.2 Strunz No: VIII/E.19-15
Locality:

Notes: