From Surf Wiki (app.surf) — the open knowledge base

Ankerite

Calcium, iron, magnesium, manganese carbonate mineral

Field	Value
name	Ankerite
image	Ankérite (Grandfontaine)-Musée de minéralogie de Strasbourg.jpg
imagesize	260px
category	Carbonate mineral
formula
IMAsymbol	Ank
strunz	5.AB.10
system	Trigonal
class	Rhombohedral ()
H–M symbol: ()
symmetry	R
unit cell	a = 4.8312(2)
c = 16.1663(3) [Å]; Z = 3
color	Brown, yellow, white
habit	Chrystals rhombohedral with curved faces; columnar, stalactitic, granular, massive
twinning	Simple t
cleavage	Perfect on {101}
fracture	Subconchoidal
tenacity	Brittle
mohs	3.5–4.0
luster	Vitreous to pearly
streak	White
diaphaneity	Translucent to transparent
gravity	2.93–3.10
opticalprop	Uniaxial (−)
refractive	nω = 1.690–1.750
nε = 1.510–1.548
birefringence	δ = 0.180–0.202
dispersion	Strong
references

H–M symbol: () c = 16.1663(3) [Å]; Z = 3 {0001}, {100}. {110} nε = 1.510–1.548 | length fast/slow = Ankerite, also known as brown spar () is a calcium, iron, magnesium, manganese carbonate mineral of the group of rhombohedral carbonates with the chemical formula . 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.

Name and history

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.

In 19th-century mineralogy, as well as in mining and among geologists, ankerite and its close analogues from the dolomite series were more often known by the capacious, expansive name of ″brown spar″. This is partly because this mineral is the extreme (with the highest content of divalent iron ions) member of the dolomite-ankerite isomorphic series, as a result of which dirty-brown varieties of dolomite, contaminated with impurities, could also be encountered under the name of brown spar.

Properties

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.

Genesis

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. 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.

It has been found in Western Tasmania, in mines in Dundas, Tasmania.

Image gallery

File:Ankerite, Pyrite - Goldmyer Hot Springs, King Co, Washington, USA.jpg|Ankerite on pyrite from King County, Washington File:Ankérite Quartz Pérou.jpg|Ankerite on quartz from Peru

References

Mineral Galleries

References

Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
[http://rruff.geo.arizona.edu/doclib/hom/ankerite.pdf Handbook of Mineralogy]
[http://www.mindat.org/min-239.html Ankerite on Mindat.org]
[http://webmineral.com/data/Ankerite.shtml Ankerite on Webmineral]
礦物學名詞: (俄英中对照試用本) Mineralogical Terminology (Russian-English-Chinese version). — Beijing: 中國科学院. 編譯出版委員会 Compilation and Publication Committee of Chinese Academy of Sciences, 1956. — 279 p.
Bulletin of the United States National Museum. No.30. Published under the Directions of the Smithsonian Institution. — Washington: Government Printing Office, 1885.
''Krivovichev V. G.'' Mineralogical glossary. Scientific editor [[:uk:Булах Андрій Глібович. A. G. Bulakh]]. — St.Petersburg: St.Petersburg Univ. Publ. House. 2009. — 556 p. — ISBN 978-5-288-04863-0
{{EB1911. Leonard James. Spencer

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

calcium-minerals magnesium-minerals iron(ii)-minerals manganese(ii)-minerals carbonate-minerals dolomite-group trigonal-minerals minerals-in-space-group-148 luminescent-minerals

Want to explore this topic further?

Ask Mako anything about Ankerite — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report