Bederite Mineral Data

General Bederite Information

Chemical Formula:

([ ],Na)Ca2(Mn++,Mg,Fe++)2(Fe+++,Mg++,Al)2Mn++2(PO4)6•2(H2O)

Composition:

Molecular Weight = 986.80 gm

Sodium 0.58 % Na 0.79 % Na₂O

Calcium 8.12 % Ca 11.37 % CaO

Magnesium 2.46 % Mg 4.08 % MgO

Manganese 16.70 % Mn 21.57 % MnO

Aluminum 0.55 % Al 1.03 % Al₂O₃

Iron 10.19 % Fe 2.18 % FeO / 12.14 % Fe₂O₃

Phosphorus 18.83 % P 43.15 % P₂O₅

Hydrogen 0.41 % H 3.65 % H₂O

Oxygen 42.15 % O

______ ______

100.00 % 99.96 % = TOTAL OXIDE

Empirical Formula:

Na_0.25Ca₂Mn²⁺Mg_0.7Fe²⁺_0.3Fe³⁺_1.5Mg_0.3Al_0.2Mn²⁺₂(PO₄)₆�2(H₂O)

Environment:

In a rare-element pegmatite of the beryl type, columbite-phosphate subtype. Isostructural with wicksite and grischunite

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

The El Penon pegmatite in the El Quemado pegmatite field, Nevados de Palermo, Salta Province, Argentina. Link to MinDat.org Location Data.

Name Origin:

For Roberto Beder (1888-1930) in recognition of his major contributions to the development of mineralogy in Argentina.

Synonym:

IMA1998-007

Bederite Image

Images:

Bederite

Comments: Dark brown massive bederite.
Location: El Penon Pegmatite, Nevados de Palermo, Salta, Argentina. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Bederite Crystallography

Axial Ratios:

a:b:c =0.9785:1:0.9127

Cell Dimensions:

a = 12.559, b = 12.834, c = 11.714, Z = 4; V = 1,888.09 Den(Calc)= 3.47

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pcab

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

By Intensity(I/I_o): 2.7682(1), 2.927(0.78), 3.006(0.67),2.8142(0.35), 2.11(0.33), 5.853(0.3),

Physical Properties of Bederite

Cleavage:

{100} Good

Color:

Very dark brown, Black.

Density:

3.48

Diaphaneity:

Transparent

Fracture:

Brittle - Irregular - Very brittle fracture producing irregular fragments

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Nodular - Tuberose forms having irregular protuberances over the surface.

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Streak:

dark olive green

Optical Properties of Bederite

Gladstone-Dale:

CI meas= 0.002 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2121,KPDmeas= 0.2115,KC= 0.2119
Ncalc = 1.74

Optical Data:

Biaxial (?), a=1.729, b=1.738, g=1.741, bire=0.0120, 2V(Calc)=58, 2V(Meas)=54. Dispersion r < v strong.

Calculated Properties of Bederite

Electron Density:

Bulk Density (Electron Density)=3.38 gm/cc
note: Specific Gravity of Bederite =3.47 gm/cc.

Fermion Index:

Fermion Index = 0.0049352436
Boson Index = 0.9950647564

Photoelectric:

PE_Bederite= 9.29 barns/electron
U=PE_Bederite x rElectron Density= 31.42 barns/cc.

Radioactivity:

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

Bederite Classification

Dana Class:

40.02.10.02 (40)Hydrated Phosphates, etc

(40.02)where A++ (B++)2 (XO4) � x(H2O)

(40.02.10)Dana Group

40.02.10.01 Wicksite NaCa2(Fe,Mn)4MgFe(PO4)6•2(H2O) P bca 2/m 2/m 2/m

40.02.10.02 Bederite! ([],Na)Ca2(Mn,Mg,Fe)2(Fe,Mg,Al)2Mn2(PO4)6•2(H2O) Pcab 2/m 2/m 2/m

40.02.10.03 Tassieite! (Na,[])Ca2(Mg,Fe,Fe)2(Fe,Mg)2(Fe,Mg)2(PO4)6(H2O)2 P bca 2/m 2/m 2/m

Strunz Class:

08.CF.05 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CF -With large and medium-sized cations, RO4:H2O > 1:1

08.CF.05 Grischunite NaCa2Mn5Fe(AsO4)6•2(H2O) Pcab 2/m 2/m 2/m

08.CF.05 Wicksite NaCa2(Fe,Mn)4MgFe(PO4)6•2(H2O) P bca 2/m 2/m 2/m

08.CF.05 Bederite! ([],Na)Ca2(Mn,Mg,Fe)2(Fe,Mg,Al)2Mn2(PO4)6•2(H2O) Pcab 2/m 2/m 2/m

08.CF.05 Tassieite! (Na,[])Ca2(Mg,Fe,Fe)2(Fe,Mg)2(Fe,Mg)2(PO4)6(H2O)2 P bca 2/m 2/m 2/m

Other Bederite Information

References:

NAME( MinRec,Vol 31, No 4) PHYS. PROP.(MinRec,Vol 31, No 4) OPTIC PROP.(MinRec,Vol 31, No 4)

See Also:

Links to other databases for Bederite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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

Bederite

([ ],Na)Ca2(Mn++,Mg,Fe++)2(Fe+++,Mg++,Al)2Mn++2(PO4)6•2(H2O)
Dana No: 40.02.10.02 Strunz No: 08.CF.05
Locality:

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