Fredrikssonite Mineral Data

Fredrikssonite Mineral Data +

General Fredrikssonite Information

Chemical Formula:

Mg2(Mn+++,Fe+++)O2(BO3)

Composition:

Molecular Weight = 194.81 gm

Magnesium 24.95 % Mg 41.38 % MgO

Manganese 14.10 % Mn 20.26 % Mn₂O₃

Iron 14.33 % Fe 20.49 % Fe₂O₃

Boron 5.55 % B 17.87 % B₂O₃

Oxygen 41.06 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₂Mn³⁺_0.5Fe³⁺_0.5O₂(BO₃)

Environment:

In dolomite.

IMA Status:

Approved IMA 1983

Locality:

Langban, Varmland, Sweden. Link to MinDat.org Location Data.

Name Origin:

Named for Kurt A. Fredriksson (1926-), Swedish-U.S. Geochemist.

Synonym:

ICSD 70102

PDF 38-412

Fredrikssonite Image

Images:

Click Here for Larger Fredrikssonite Image

Fredrikssonite Hausmannite

Comments: Red-brown elongated crystalline fredrikssonite in calcite with granular hausmannite.
Location: Langban, Varmland, Sweden. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Fredrikssonite Crystallography

Axial Ratios:

a:b:c =0.7311:1:0.2352

Cell Dimensions:

a = 9.18, b = 12.555, c = 2.954, Z = 4; V = 340.46 Den(Calc)= 3.80

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pbam

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

By Intensity(I/I_o): 2.59(1), 2.486(0.9), 5.16(0.8),

Crystal Structure:

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Burns P C , Cooper M A , Hawthorne F C , The Canadian Mineralogist , 32 (1994) p.397-403, Jahn-Teller-distorted MnO6 octahedra in fredrikssonite, the fourth polymorph, of Mg2Mn(BO3)O2

Physical Properties of Fredrikssonite

Cleavage:

[???] Poor, [???] Indistinct

Color:

Reddish brown.

Density:

3.84

Diaphaniety:

Translucent

Habit:

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

Hardness:

6 - Orthoclase

Luster:

Vitreous (Glassy)

Streak:

yellowish brown

Optical Properties of Fredrikssonite

Gladstone-Dale:

CI meas= 0.061 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.051 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2342,KPDmeas= 0.2318,KC= 0.2467

Optical Data:

Biaxial (+), a=1.82, b=1.86, g=1.99, bire=0.1700, 2V(Calc)=62, 2V(Meas)=51.

Pleochroism (x):

golden brown.

Pleochroism (y):

dark reddish brown.

Pleochroism (z):

black.

Calculated Properties of Fredrikssonite

Electron Density:

r_electron=3.69 gm/cc
note: r_{Fredrikssonite}=3.80 gm/cc.

Fermion Index

Fermion Index = 0.03923
Boson Index = 0.96077

Photoelectric:

PE_{Fredrikssonite}= 8.51 barns/electron
U=PE_{Fredrikssonite} x r_electron= 31.39 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Fredrikssonite is Not Radioactive

Fredrikssonite Classification

Dana Class:

24.2.1.6 (24)Borates - Anhydrous

(24.2)where (A)2 BO2 [XO3]

(24.2.1)Ludwigite Group (Space Group: Pbam)

24.2.1.1 Ludwigite Mg2FeBO5 Pbam 2/m 2/m 2/m

24.2.1.2 Vonsenite Fe2FeBO5 Pbam 2/m 2/m 2/m

24.2.1.3 Azoproite (Mg,Fe)2(Fe,Ti,Mg)BO5 Pbam 2/m 2/m 2/m

24.2.1.4 Bonaccordite Ni2FeBO5 Pbam 2/m 2/m 2/m

24.2.1.5 Chestermanite Mg2(Fe,Mg,Al,Sb)BO3O2 Pbam 2/m 2/m 2/m

24.2.1.6 Fredrikssonite Mg2(Mn,Fe)O2(BO3) Pbam 2/m 2/m 2/m

Strunz Class:

V/G.04-50 V - Nitrates, Carbonates and Borates

V/G - "Insel" borates [BO3]3- "inseln"

V/G.04 - Ludwigite group

V/G.04-10 Ludwigite Mg2FeBO5 Pbam 2/m 2/m 2/m

V/G.04-20 Vonsenite Fe2FeBO5 Pbam 2/m 2/m 2/m

V/G.04-30 Azoproite (Mg,Fe)2(Fe,Ti,Mg)BO5 Pbam 2/m 2/m 2/m

V/G.04-40 Chestermanite Mg2(Fe,Mg,Al,Sb)BO3O2 Pbam 2/m 2/m 2/m

V/G.04-50 Fredrikssonite Mg2(Mn,Fe)O2(BO3) Pbam 2/m 2/m 2/m

V/G.04-60 Bonaccordite Ni2FeBO5 Pbam 2/m 2/m 2/m

V/G.04-70 Takeuchiite Mg2MnO2(BO3) Pnnm 2/m 2/m 2/m

V/G.04-80 Orthopinakiolite (Mg,Mn)2MnBO5 Pnnm 2/m 2/m 2/m

V/G.04-90 Blatterite (Mn,Mg)35Sb3(Mn,Fe)9(BO3)16O32 Pnnm 2/m 2/m 2/m

V/G.04-100 Gaudefroyite Ca4Mn3-x(BO3)3(CO3)(O,OH)3 P 6₃ 6

Other Fredrikssonite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Fredrikssonite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - Scandinavian mineral gallery 13 - WWW-MINCRYST 14 -École des Mines de Paris

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Fredrikssonite

Mg2(Mn+++,Fe+++)O2(BO3)
Dana No: 24.2.1.6 Strunz No: V/G.04-50
Locality:

Notes: