Barbertonite Mineral Data

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)

Environment:

Alteration product of chromite in serpentinite.

IMA Status:

Valid Species (Pre-IMA) 1940

Locality:

Kaapsehoop asbestos mine, Kaapse Hoop, Barberton district, Transvaal, South Africa. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Barbertonite + Pronunciation

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

Diaphaneity:

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
Ncalc = 1.56 - 1.57

Optical Data:

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

Calculated Properties of Barbertonite

Electron Density:

Bulk Density (Electron Density)=2.14 gm/cc
note: Specific Gravity of Barbertonite =2.10 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Barbertonite= 4.01 barns/electron
U=PE_Barbertonite x rElectron Density= 8.59 barns/cc.

Radioactivity:

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

Barbertonite Classification

Dana Class:

16b.06.01.02 (16b)Carbonates - Hydroxyl or Halogen

(16b.06)Dana Type

(16b.06.01)Sjorgrenite-Hydrotalcite Group (Sojogrenite Subgroup:Hexagonal)

16b.06.01.01 Manasseite Mg6Al2(CO3)(OH)16•4(H2O) P 6₃/mmc 6/m 2/m 2/m

16b.06.01.02 Barbertonite Mg6Cr2(CO3)(OH)16•4(H2O) P 6₃/mmc 6/m 2/m 2/m

16b.06.01.03 Sjogrenite Mg6Fe2(CO3)(OH)16•4(H2O) P 6₃/mmc 6/m 2/m 2/m

16b.06.01.04 Zaccagnaite! Zn4Al2(OH)12(CO3)•3(H2O) P 6₃/mmc 6/m 2/m 2/m

Strunz Class:

05.DA.45 05 - CARBONATES (NITRATES)

05.D - Carbonates with Additional Anions, with H2O

05.DA -With medium-sized cations

05.DA.45 Brugnatellite Mg6Fe(CO3)(OH)13•4(H2O) P 6₃/mmc 6/m 2/m 2/m

05.DA.45 Barbertonite Mg6Cr2(CO3)(OH)16•4(H2O) P 6₃/mmc 6/m 2/m 2/m

05.DA.45 Chlormagaluminite (Mg,Fe)4Al2(OH)12(Cl2,CO3)•2(H2O) P 6/mcm, P 6cm, P 6c2 Hex

05.DA.45 Zaccagnaite! Zn4Al2(OH)12(CO3)•3(H2O) P 6₃/mmc 6/m 2/m 2/m

05.DA.45 Manasseite Mg6Al2(CO3)(OH)16•4(H2O) P 6₃/mmc 6/m 2/m 2/m

05.DA.45 Sjogrenite Mg6Fe2(CO3)(OH)16•4(H2O) P 6₃/mmc 6/m 2/m 2/m

Other Barbertonite Information

References:

NAME( AntBidBlaNic3) 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 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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

Barbertonite

Mg6Cr2(CO3)(OH)16•4(H2O)
Dana No: 16b.06.01.02 Strunz No: 05.DA.45
Locality:

Notes: