Mindat Logo

Ankerite

This page is currently not sponsored. Click here to sponsor this page.



Formula:
Ca(Fe
2+
 
,Mg)(CO
 
3
)
 
2
Usually contains minor Mg and/or Mn.
System:TrigonalColour:Brown, white to grey, ...
Lustre:Vitreous, PearlyHardness:3½ - 4
Member of:Dolomite Group
Name:
Named after Mathias J. Anker (1771-1843), Styrian (Austria) mineralogist.


Dolomite Group. Ankerite-Dolomite Series, and the Ankerite-Kutnohorite Series.

Note: Most (unanalysed) "ankerite" specimens are usually Fe-bearing (ferroan) dolomite (Mg>Fe).

Crystals of the composition CaFe(CO3)2 have neither been synthesized (Goldsmith et al., 1962; Rosenberg, 1967) nor have they been found in nature (Dana's System of Mineralogy, Vol. II, 1951; Deer et al., 1962; Goldsmith et al., 1962; Beran, 1975).

Classification of Ankerite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:5/B.03-20
Nickel-Strunz 10th (pending) edition ID:5.AB.10

5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
B : Alkali-earth (and other M2+) carbonates
Dana 7th edition ID:14.2.1.2
Dana 8th edition ID:14.2.1.2

14 : ANHYDROUS NORMAL CARBONATES
2 : AB(XO3)2
Hey's CIM Ref.:11.13.6

11 : Carbonates
13 : Carbonates of Fe
mindat.org URL:http://www.mindat.org/min-239.html
Please feel free to link to this page.

Type Occurrence of Ankerite

Type Locality:Styrian Erzberg, Eisenerz, Styria, Austria
Year of Discovery:1825

Occurrences of Ankerite

Geological Setting:Low grade metamorphism of ironstones and banded iron formation.

Physical Properties of Ankerite

Lustre:Vitreous, Pearly
Diaphaneity (Transparency):Transparent, Translucent
Colour:Brown, white to grey, yellowish-brown, tan.
Streak:White
Hardness (Mohs):3½ - 4
Tenacity:Brittle
Cleavage:Perfect
Perfect on {1011}
Fracture:Sub-Conchoidal
Density (measured):2.93 - 3.1 g/cm3
Density (calculated):3.11 g/cm3

Crystallography of Ankerite

Crystal System:Trigonal
Class (H-M):3 - Rhombohedral
Space Group:R3
Cell Parameters:a = 4.8312(2) Å, c = 16.1663(3) Å
Ratio:a:c = 1 : 3.346
Unit Cell Volume:V 326.78 ų (Calculated from Unit Cell)
Z:3
Morphology:Crystals commonly rhombohedral with {1011} or, less commonly, {4041} dominant.
Twinning:Simple twins on {0001}, {1010}. {1120}
Comment:For sample with 68 mol% CaFe(CO3)2 (Reeder & Dollase, 1989). A sample with ca. 70 mol% CaFe(CO3)2 has a = 4.836 and 16.186 A (Ross & Reeder, 1992).
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Ankerite

Type:Uniaxial (-)
RI values: nω = 1.690 - 1.750 nε = 1.510 - 1.548
Maximum Birefringence:δ = 0.180 - 0.202

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:Strong

Chemical Properties of Ankerite

Formula:
Ca(Fe
2+
 
,Mg)(CO
 
3
)
 
2


Usually contains minor Mg and/or Mn.
Simplified for copy/paste:Ca(Fe2+,Mg)(CO3)2
Essential elements:C, Ca, Fe, O
All elements listed in formula:C, Ca, Fe, Mg, O
Common Impurities:Ce,La,TR

Relationship of Ankerite to other Species

Series:Forms a series with Dolomite (see here)
Forms a series with Kutnohorite (see here)
Member of:Dolomite Group
Other Members of Group:

- +
Dolomite
CaMg(CO
 
3
)
 
2
Kutnohorite
Ca(Mn,Mg,Fe)(CO
 
3
)
 
2
Minrecordite
CaZn(CO
 
3
)
 
2
Norsethite
BaMg(CO
 
3
)
 
2
Related Minerals - Nickel-Strunz Grouping):

- +
5.AB.05Calcite
CaCO
 
3
5.AB.05Gaspéite
(Ni,Mg,Fe)CO
 
3
5.AB.05Magnesite
MgCO
 
3
5.AB.05Otavite
CdCO
 
3
5.AB.05Rhodochrosite
MnCO
 
3
5.AB.05Siderite
FeCO
 
3
5.AB.05Smithsonite
ZnCO
 
3
5.AB.05Spherocobaltite
CoCO
 
3
5.AB.10Dolomite
CaMg(CO
 
3
)
 
2
5.AB.10Kutnohorite
Ca(Mn,Mg,Fe)(CO
 
3
)
 
2
5.AB.10Minrecordite
CaZn(CO
 
3
)
 
2
5.AB.15Aragonite
CaCO
 
3
5.AB.15Cerussite
PbCO
 
3
5.AB.15Strontianite
SrCO
 
3
5.AB.15Witherite
BaCO
 
3
5.AB.20Vaterite
CaCO
 
3
5.AB.25Huntite
CaMg
 
3
(CO
 
3
)
 
4
5.AB.30Norsethite
BaMg(CO
 
3
)
 
2
5.AB.35Alstonite
BaCa(CO
 
3
)
 
2
5.AB.40Olekminskite
Sr(Sr,Ca,Ba)(CO
 
3
)
 
2
5.AB.40Paralstonite
BaCa(CO
 
3
)
 
2
5.AB.45Barytocalcite
BaCa(CO
 
3
)
 
2
5.AB.50Carbocernaite
(Ca,Na)(Sr,Ce,Ba)(CO
 
3
)
 
2
5.AB.55Benstonite
(Ba,Sr)
 
6
(Ca,Mn)
 
6
Mg(CO
 
3
)
 
13
5.AB.60Juangodoyite
Na
 
2
Cu(CO
 
3
)
 
2
Related Minerals - Hey's Index Grouping:

- +
11.13.1Siderite
FeCO
 
3
11.13.2Pyroaurite
Mg
 
6
Fe
3+
2
(OH)
 
16
[CO
 
3
] · 4H
 
2
O
11.13.3Pyroaurite-2H
Mg
 
6
Fe
3+
2
(CO
 
3
)(OH)
 
16
· 4H
 
2
O
11.13.4Brugnatellite
Mg
 
6
Fe
3+
 
(CO
 
3
)(OH)
 
13
· 4H
 
2
O
11.13.5Coalingite
Mg
 
10
Fe
3+
2
(OH)
 
24
[CO
 
3
] · 2H
 
2
O
Related Minerals - Dana Grouping):

- +
14.2.1.1Dolomite
CaMg(CO
 
3
)
 
2

Other Names for Ankerite

Other Languages:
Catalan:Ankerita
Dutch:Ankeriet
French:Ankérite
German:Ankerit
Eisendolomit
Tautoklin
Hungarian:Ankerit
Italian:Ankerite
Lithuanian:Ankeritas
Polish:Ankeryt
Russian:Анкерит
Simplified Chinese:铁白云石
Slovak:Ankerit
Spanish:Ankerita
Swedish:Ankerit
Ukrainian:Анкерит
Varieties:
Manganoan AnkeriteNickeliferous Ankerite

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Ankerite

Reference List:

- +
Rocza (1926) Zentralblatt Mineralien: 229.

Winchell (1927) part 2: 75.

Larsen, E.S. and Berman, H. (1934) The Microscopic Determination of the Nonopaque Minerals, Second edition, USGS Bulletin 848: 229.

Palache, C., Berman, H., & Frondel, C. (1951) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 208-217.

Goldsmith, J.R., D.L. Graf, J. Witters & D.A. Northrop (1962) Studies in the system CaCO3•MgCO3•FeCO3: (1) Phase relations; (2) A method for major element spectrochemical analyses; and, (3) Composition of some ferroan dolomites. Journal of Geology: 70: 659-688.

Tschermaks Mineralogische und Petrographische Mitteilungen 24: 279-286.

Reeder, R., Dollase, W. (1989): Structural variation in the dolomite-ankerite solid-solution series: An X-ray, Mössbauer, and TEM study. Am. Mineral. 74, 1159-1167.

Walmsley, J.C. and Lang, A.R. (1992) On submicrometer inclusions in diamond coat: Crystallography and composition of ankerites and related rhombohedral carbonates. Mineralogical Magazine: 56: 533-543.

Ross, N. L. & Reeder, R. (1992): High-pressure structural study of dolomite and ankerite. American Mineralogist, 77, 412-421.

Mindat.org articles about Ankerite

Article entries:
X-Ray Diffraction of Keokuk Geode Samples, Part 2 of 3Keith A. Peregrine

Internet Links for Ankerite

Search Engines:
  • Look for Ankerite on Google
  • Look for Ankerite images on Google
  • External Links:
  • Look for Ankerite on Webmineral
  • Look for Ankerite on Athena Mineralogy
  • Look for Ankerite on Wikipedia
  • Look for Ankerite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Ankerite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Fine and rare minerals from mintreasure.com
  • Buy rare minerals from Excalibur Minerals
  • Buy from David K Joyce minerals
  • Buy RARE Minerals from Rocks of Africa
  • Search for Ankerite on Well-Arranged Molecules
  • rare and unusual minerals mainly crystallized
  • SpiriferMinerals.com - high quality low prices
  • Ankerite specimens for sale - minfind.com
  • Buy from Dave Bunk Minerals
  • Top quality minerals from Kristalle of California
  • Buy from McDougall Minerals
  • Find Ankerite on www.crystalclassics.co.uk
  • Localities for Ankerite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    Mineral and/or Locality  
    Search Google  
    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
    Current server date and time: October 30, 2014 10:14:15
    Mineral and Locality Search
    Mineral:
    and/or Locality:
    Options
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds