Fluorcalciopyrochlore

Where it forms, where it's found

Geological setting: A dolomite-type niobium rare-earth ore deposit.
Type locality: Bayan Obo deposit
Bayan Obo mining district
Baotou City
Inner Mongolia
China
41.7958°, 109.9694°

31recorded occurrences

Source · OpenStreetMap

Physical

Hardness: 1Talc
2Gypsum
3Calcite
4Fluorite
5Apatite
6Orthoclase
7Quartz
8Topaz
9Corundum
10Diamond
Transparency: Transparent · Translucent
Colour: Brownish-yellow to reddish-orange
Streak: Light yellow
Cleavage: None Observed
Fracture: Conchoidal
Density: 4.34 g/cm³

Crystallography

Crystal system: Isometric
Cell parameters: a = 10.4164(9) Å
Morphology: As octahedra (111), dodecahedra (110), and cubes (100), or combinations thereof, and generally range in size from 0.01 to 0.3 mm
Parting: None observed
Type-locality form: As octahedra (111), dodecahedra (110), and cubes (100), or combinations thereof, and generally range in size from 0.01 to 0.3 mm
Comment: Fd3¯ m

Crystal structure

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
41NbNiobium Niobium 2 92.906 185.812
35.55%
8OOxygen Oxygen 6 15.999 95.994
18.37%
22TiTitanium Titanium 2 47.867 95.734
18.32%
20CaCalcium Calcium 2 40.078 80.156
15.33%
11NaSodium Sodium 2 22.990 45.980
8.80%
9FFluorine Fluorine 1 18.998 18.998
3.63%
Total 522.674 100.00%
Mass share = atoms × atomic mass ÷ molar mass × 100
From IMA formula

Mass composition breakdown
Element	Atoms	At. mass g/mol	Mass g/mol	Mass share
41NbNiobium	Niobium	2	92.906	185.812	35.55%
8OOxygen	Oxygen	6	15.999	95.994	18.37%
22TiTitanium	Titanium	2	47.867	95.734	18.32%
20CaCalcium	Calcium	2	40.078	80.156	15.33%
11NaSodium	Sodium	2	22.990	45.980	8.80%
9FFluorine	Fluorine	1	18.998	18.998	3.63%
	Total	522.674	100.00%

Synonyms

Fluorcalciopyrochloor
IMA2013-055

In other languages

German: Fluorcalciopyrochlor · IMA 2013-055
Italian: fluorcalciopyrochlore

Classification

Strunz

10th ed.

4.DH.15

4OxidesClass
4.DMetal: Oxygen = 1:2 and similarDivision
4.DHWith large (+- medium-sized) cations; sheets of edge-sharing octahedraGroup
4.DH.15FluorcalciopyrochloreSpecies

Group, growth & confusion

11 members

Literature, links & citation

Citations

1826Annalen Physik Chemie, (Poggendorff) (1826) 7, 417-427.
2010Atencio, D., Andrade, M. B., Christy, A. G., Giere, R., Kartashov, P. M. (2010) The pyrochlore supergroup of minerals: nomenclature. The Canadian Mineralogist, 48 (3) 673-698 doi:10.3749/canmin.48.3.673 DOI: 10.3749/canmin.48.3.673
2013Christy, A. G., Atencio, D. (2013) Clarification of status of species in the pyrochlore supergroup. Mineralogical Magazine, 77 (1) 13-20 doi:10.1180/minmag.2013.077.1.02 DOI: 10.1180/minmag.2013.077.1.02
2013Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No.17. Mineralogical Magazine, 77 (7) 2997-3005 doi:10.1180/minmag.2013.077.7.09DOI: 10.1180/minmag.2013.077.7.09
2016Guowu, Li, Guangming, Yang, Fude, Lu, Ming, Xiong, Xiangkun, Ge, Baoming, Pan, de Fourestier, Jeffrey (2016) Fluorcalciopyrochlore, A New Mineral Species From Bayan Obo, Inner Mongolia, P.R. China. The Canadian Mineralogist, 54 (5) 1285-1291 doi:10.3749/canmin.1500042DOI: 10.3749/canmin.1500042

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Fluorcalciopyrochlore — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/fluorcalciopyrochlore-40341},
  note      = {Accessed 2026-05-11}
}