Ankerite Mineral Data

General Ankerite Information

Chemical Formula:

Ca(Fe++,Mg,Mn)(CO3)2

Composition:

Molecular Weight = 206.39 gm

Calcium 19.42 % Ca 27.17 % CaO

Magnesium 3.53 % Mg 5.86 % MgO

Manganese 2.66 % Mn 3.44 % MnO

Iron 16.24 % Fe 20.89 % FeO

Carbon 11.64 % C 42.65 % CO₂

Oxygen 46.51 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaFe²⁺_0.6Mg_0.3Mn²⁺_0.1(CO₃)₂

Environment:

Common in ore-bearing rocks as a rock forming mineral (gangue). High Fe species are found in iron ores.

IMA Status:

Valid Species (Pre-IMA) 1825

Locality:

Styrian Erzberg, Eisenerz, Styria, Austria Link to MinDat.org Location Data.

Name Origin:

Named after the Styrian (Austrian) mineralogist, Mathias Joseph Anker (1771-1843).

Name Pronunciation:

Ankerite

Synonym:

Brown Spar

ICSD 100417

PDF 41-586

Ankerite Image

Images:

Ankerite Sphalerite Dickite

Comments: White, rhombohedral crystals of ankerite and dark gray, metallic sphalerite on beige dickite.
Location: Prego mine, Kladno, Czech Rebublic. Scale: Picture size 2 cm.
© Dave Barthelmy

Ankerite Crystallography

Axial Ratios:

a:c = 1:3.3472

Cell Dimensions:

a = 4.83, c = 16.167, Z = 3; V = 326.63 Den(Calc)= 3.15

Crystal System:

Trigonal - Rhombohedral H-M Symbol ( 3) Space Group: R 3

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

By Intensity(I/I_o): 2.899(1), 1.812(0.06), 2.199(0.06),

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Forms: ( 1 0 1)

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Physical Properties of Ankerite

Cleavage:

{1011} Perfect, {1011} Perfect, {1011} Perfect

Color:

Brown, Brownish yellow, Gray, Gray brown, White.

Density:

3 - 3.1, Average = 3.05

Diaphaneity:

Translucent to subtranslucent

Fracture:

Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.

Habit:

Crystalline - Coarse - Occurs as well-formed coarse sized crystals.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Ankerite

Gladstone-Dale:

CI meas= -0.001 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.031 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1984,KPDmeas= 0.2049,KC= 0.2048
Ncalc = 1.61 - 1.65

Optical Data:

Uniaxial (-), e=1.51-1.55, w=1.69-1.75, bire=0.1800-0.2000.

Calculated Properties of Ankerite

Electron Density:

Bulk Density (Electron Density)=3.01 gm/cc
note: Specific Gravity of Ankerite =3.05 gm/cc.

Fermion Index:

Fermion Index = 0.0087404925
Boson Index = 0.9912595075

Photoelectric:

PE_Ankerite= 8.09 barns/electron
U=PE_Ankerite x rElectron Density= 24.33 barns/cc.

Radioactivity:

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

Ankerite Classification

Dana Class:

14.02.01.02 (14)Anhydrous Carbonates

(14.02)with Compound Formula A+ B++ (CO3)2

(14.02.01)Dolomite Group (Trigonal: R-3)

14.02.01.01 Dolomite CaMg(CO3)2 R 3 3

14.02.01.02 Ankerite Ca(Fe,Mg,Mn)(CO3)2 R 3 3

14.02.01.03 Kutnohorite Ca(Mn,Mg,Fe)(CO3)2 R 3 3

14.02.01.04 Minrecordite CaZn(CO3)2 R 3 3

Strunz Class:

05.AB.10 05 - CARBONATES (NITRATES)

05.A - Carbonates without additional anions, without H2O

05.AB -Alkali-earth (and other M2+) carbonates

05.AB.10 Ankerite Ca(Fe,Mg,Mn)(CO3)2 R 3 3

05.AB.10 Dolomite CaMg(CO3)2 R 3 3

05.AB.10 Kutnohorite Ca(Mn,Mg,Fe)(CO3)2 R 3 3

05.AB.10 Minrecordite CaZn(CO3)2 R 3 3

Other Ankerite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Dana8) OPTIC PROP.(Mason68)

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Ankerite

Ca(Fe++,Mg,Mn)(CO3)2
Dana No: 14.02.01.02 Strunz No: 05.AB.10
Locality:

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