Calcium, iron, magnesium, manganese carbonate mineral
Ankerite
General
Category
Carbonate mineral
Formula (repeating unit)
Ca(Fe,Mg,Mn)(CO3)2
IMA symbol
Ank[1]
Strunz classification
5.AB.10
Crystal system
Trigonal
Crystal class
Rhombohedral (3) H–M symbol: (3)
Space group
R3
Unit cell
a = 4.8312(2) c = 16.1663(3) [Å]; Z = 3
Identification
Color
Brown, yellow, white
Crystal habit
Chrystals rhombohedral with curved faces; columnar, stalactitic, granular, massive
Twinning
Simple t
{0001}, {1010}. {1120}
Cleavage
Perfect on {1011}
Fracture
Subconchoidal
Tenacity
Brittle
Mohs scale hardness
3.5–4.0
Luster
Vitreous to pearly
Streak
White
Diaphaneity
Translucent to transparent
Specific gravity
2.93–3.10
Optical properties
Uniaxial (−)
Refractive index
nω = 1.690–1.750 nε = 1.510–1.548
Birefringence
δ = 0.180–0.202
Dispersion
Strong
References
[2][3][4]
Ankerite is a calcium, iron, magnesium, manganese carbonate mineral of the group of rhombohedral carbonates with the chemical formula Ca(Fe,Mg,Mn)(CO3)2. In composition it is closely related to dolomite, but differs from this in having magnesium replaced by varying amounts of iron(II) and manganese. It forms a series with dolomite and kutnohorite.[3]
The crystallographic and physical characters resemble those of dolomite and siderite. The angle between the perfect rhombohedral cleavages is 73° 48′, the hardness is 3.5 to 4, and the specific gravity is 2.9 to 3.1. The color is white, grey or reddish to yellowish brown.[5]
Ankerite occurs with siderite in metamorphosed ironstones and sedimentary banded iron formations. It also occurs in carbonatites. In sediments it occurs as authigenic, diagenetic minerals and as a product of hydrothermal deposition.[2] It is one of the minerals of the dolomite-siderite series, to which the terms brown-spar, pearl-spar and bitter-spar have been historically loosely applied.[5]
It was first recognized as a distinct species by Wilhelm von Haidinger in 1825, and named for Matthias Joseph Anker (1771–1843) of Styria, an Austrian mineralogist.[3]
It has been found in Western Tasmania, in mines in Dundas, Tasmania.
^ abOne or more of the preceding sentences incorporates text from a publication now in the public domain: Spencer, Leonard James (1911). "Ankerite". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 2 (11th ed.). Cambridge University Press. p. 58.
Ankerite is a calcium, iron, magnesium, manganese carbonate mineral of the group of rhombohedral carbonates with the chemical formula Ca(Fe,Mg,Mn)(CO3)2...
defined as ankerite. The exact delineation between which minerals are considered ferroan dolomite and which are ankerite is unclear. Ankerite with the "pure"...
metamorphic rocks; and with grunerite, magnetite, hematite, stilpnomelane, ankerite, siderite, calcite, chalcedonic quartz in iron formations. The riebeckite...
suggests. A railroad station once existed at the bottom of the hill. Buffalo Ankerite is an old mining area and there are some homes. There is also a lake near...
galena, pyrite, marcasite, arsenopyrite, cervantite, stibiconite, calcite, ankerite, barite and chalcedony. Small deposits of stibnite are common, but large...
andradite, aegirine, microcline, sanidine, albite, calcite, fluorite, ankerite and baryte. Significant deposits of fine material are restricted to but...
These released elements form authigenic quartz, chert, calcite, dolomite, ankerite, hematite and albite, all trace to minor (except quartz) minerals found...
oxides or hydroxides (such as goethite and hematite), dolomite, siderite, ankerite, marcasite, barite, and gypsum. Although concretions often consist of a...
composition. The terms rauhaugite and beforsite refer to dolomite- and ankerite-rich occurrences respectively. The alkali-carbonatites are termed lengaite...
magnetite), the iron sediment may contain the iron-rich carbonates siderite and ankerite, or the iron-rich silicates minnesotaite and greenalite. Most BIFs are...
buried with "over 1070 shabtis of varying sizes and made of granite, green ankerite, and alabaster." Taharqa began cultivating alliances with elements in Phoenicia...
member of the dolomite group. It forms a series with dolomite, and with ankerite. The end member formula is CaMn2+(CO3)2, but Mg2+ and Fe2+ commonly substitute...
rutile and ilmenite, and variants of glimmerite bearing graphite, spinel, ankerite, pyrite, apatite, and the carbonate minerals calcite and dolomite have...
alters to baryte, which in its turn alters to witherite. Ankerite Ca(Fe,Mg)(CO3)2: Ankerite occurs as brownish rhombohedral crystals on quartz. Aragonite...
metamorphosed. Banded iron formations may contain iron in carbonates (siderite or ankerite) or silicates (minnesotaite, greenalite, or grunerite), but in those mined...
sale but the sale was controversial as NUS held a 16 percent stake in Ankerite, a private fund that was a subsidiary of CapitaLand. The Interlace was...
Styria (1835). In 1825, Wilhelm von Haidinger (1795–1871) named the mineral ankerite in his honor. Kurze Darstellung einer Mineralogie von Steiermark (Outline...
carbonate veins containing one or more of magnesite, calcite, dolomite, ankerite, and/or siderite. Original pyroxene and olivine in the peridotite are commonly...
rare phase in carbonatites. It occurs associated with calcite, baryte, ankerite, siderite, benstonite, galena, sphalerite, pyrite, and quartz. USA: Tiny...
development of hydrothermal breccias, quartz and carbonate veining and pervasive ankerite-siderite-chlorite-sericite alteration. The feeders themselves do not need...
with the Buffalo Ankerites, a team in a mines league that played in mining towns in northern Ontario and Quebec. While with the Ankerites, Carnegie was part...
Sheppard, S.M.F (June 1986). "An isotopic study of siderites, dolomites and ankerites at high temperatures". Geochimica et Cosmochimica Acta. 50 (6): 1147–1150...
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