Barbertonite Mineral Data

Barbertonite Mineral Data +

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General Barbertonite Information

Chemical Formula:

Mg6Cr2(CO3)(OH)16·4(H2O)

Composition:

Molecular Weight = 654.01 gm

Magnesium 22.30 % Mg 36.98 % MgO

Chromium 15.90 % Cr 23.24 % Cr₂O₃

Hydrogen 3.70 % H 33.06 % H₂O

Carbon 1.84 % C 6.73 % CO₂

Oxygen 56.27 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₆Cr₂(CO₃)(OH)₁₆·4(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1940

Locality:

Link to MinDat.org Location Data.

Barbertonite Image

Images:

Barbertonite

Comments: Crystalline, red barbertonite in white and green serpentinite rock.
Location: Nevada Creek, Tasmania, Australia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Barbertonite Crystallography

Axial Ratios:

a:c = 1:2.51539

Cell Dimensions:

a = 6.17, c = 15.52, Z = 1; V = 511.67 Den(Calc)= 2.12

Crystal System:

Hexagonal - Dihexagonal DipyramidalH-M Symbol (6/m 2/m 2/m) Space Group: P 6₃/mmc

Physical Properties of Barbertonite

Cleavage:

[001] Perfect

Color:

Violet, Pink, Pink violet.

Density:

2.1

Diaphaniety:

Transparent to Translucent

Fracture:

Flexible - Flexible fragments.

Hardness:

1.5-2 - Talc-Gypsum

Luster:

Pearly

Streak:

white

Optical Properties of Barbertonite

Gladstone-Dale:

CI meas= 0.035 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.044 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2561,KPDmeas= 0.2586,KC= 0.2679

Optical Data:

Uniaxial (-), e=1.529, w=1.557, bire=0.0280.

Calculated Properties of Barbertonite

Electron Density:

r_electron=2.14 gm/cc
note: r_Barbertonite=2.10 gm/cc.

Fermion Index

Fermion Index = 0.03788
Boson Index = 0.96212

Photoelectric:

PE_Barbertonite= 4.01 barns/electron
U=PE_Barbertonite x r_electron= 8.59 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Barbertonite is Not Radioactive

Barbertonite Classification

Dana Class:

16b.6.1.2 (16b)Carbonates - Hydroxyl or Halogen

(16b.6)Dana Type

(16b.6.1)Sjorgrenite-Hydrotalcite Group (Sojogrenite Subgroup:Hexagonal)

16b.6.1.1 Manasseite Mg6Al2(CO3)(OH)16·4(H2O) P 6₃/mmc 6/m 2/m 2/m

16b.6.1.2 Barbertonite Mg6Cr2(CO3)(OH)16·4(H2O) P 6₃/mmc 6/m 2/m 2/m

16b.6.1.3 Sjogrenite Mg6Fe2(CO3)(OH)14·5(H2O) P 6₃/mmc 6/m 2/m 2/m

16b.6.1.4 Zaccagnaite! Zn4Al2(OH)12(CO3)·3(H2O) P 6₃/mmc 6/m 2/m 2/m

Strunz Class:

V/E.02-30 V - Nitrates, Carbonates and Borates

V/E - Water-bearing carbonates with unfamiliar anions

V/E.02 - Manasseite group

V/E.02-05 Quintinite-2H Mg4Al2(OH)12CO3·4(H2O) P 6₃22 6 2 2

V/E.02-05* Quintinite-3T Mg4Al2(OH)12CO3·4(H2O) P 3₁12,P 3₂12 3 2

V/E.02-07 Caresite Fe4Al2(OH)12CO3·3(H2O) P 3₁12 or P 3₂12 3 2

V/E.02-08 Charmarite-2H Mn4Al2(CO3)(OH)12·3(H2O) P 6₃22 6 2 2

V/E.02-08* Charmarite-3T Mn4Al2(CO3)(OH)12·3(H2O) P 3₁12 3 2

V/E.02-09 Zaccagnaite! Zn4Al2(OH)12(CO3)·3(H2O) P 6₃/mmc 6/m 2/m 2/m

V/E.02-10 Manasseite Mg6Al2(CO3)(OH)16·4(H2O) P 6₃/mmc 6/m 2/m 2/m

V/E.02-20 Chlormagaluminite (Mg,Fe)4Al2(OH)12(Cl2,CO3)·2(H2O) P 6/mcm, P 6cm, P 6c2 Hex

V/E.02-30 Barbertonite Mg6Cr2(CO3)(OH)16·4(H2O) P 6₃/mmc 6/m 2/m 2/m

V/E.02-40 Sjogrenite Mg6Fe2(CO3)(OH)14·5(H2O) P 6₃/mmc 6/m 2/m 2/m

Other Barbertonite Information

References:

PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

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

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

Barbertonite

Mg6Cr2(CO3)(OH)16·4(H2O)
Dana No: 16b.6.1.2 Strunz No: V/E.02-30
Locality:

Notes: