History
The name carries a confession. It comes from the Greek synchys — confounding — chosen because the mineral was so easily mistaken for another. That other was parisite, a close chemical cousin: both are rare-earth fluorocarbonates, minerals built from calcium, cerium, carbonate and fluorine in similar proportions. The two grow tangled together in the same rock, and early mineralogists could not always tell them apart.
The Swedish mineralogist Gustaf Flink first found it in 1900, in syenitic pegmatites at Narssarssuk in Greenland. He published the name the following year, in 1901. The first specimens came from those Greenland pegmatites — coarse-grained igneous rocks rich in rare-earth elements, the family of metals that includes cerium and lanthanum.
The suffix -(Ce) is a later addition. Mineralogists use it to flag which rare-earth element dominates the recipe — here, cerium. The International Mineralogical Association formalised that cerium-dominant species in 1982, fixing the name as synchysite-(Ce) and distinguishing it from its yttrium-rich twin, synchysite-(Y).
Industrial & practical applications
Synchysite-(Ce) is a minor ore of the rare-earth elements — the family of metals, cerium and lanthanum among them, that goes into magnets, catalysts and phosphors. It is rarely the main prize. The bulk of the world's rare earths comes from two other minerals: bastnäsite, a related fluorocarbonate, and monazite, a phosphate. Synchysite-(Ce) sits behind both as a secondary source, worth recovering only where it concentrates.
It does concentrate in a few places. In the Lugiin Gol deposit of southern Mongolia, synchysite-(Ce) is the most abundant rare-earth fluorocarbonate, making up about 11 percent of an ore body estimated at 500,000 tonnes. There it is mined alongside its intergrown cousins, bastnäsite-(Ce) and parisite-(Ce), as part of a mixed rare-earth concentrate rather than on its own.
Beyond such deposits, the mineral's main pull is for collectors and researchers. Its tendency to grow tangled with parisite, bastnäsite and röntgenite makes it a subject of study in how these rare-earth carbonates form and separate.
Where it forms, where it's found
- Geological setting
Pegmatitic segregations in syenite.
Hydrothermal accessory mineral in granites and alkalic syenites.
- Type locality
- Narssârssuk pegmatite
- Narsaarsuk Plateau
- Igaliku
- Kujalleq
- Greenland
61.0331°, -45.3778°
Physical
Optical
- Optical type
- Uniaxial (+)
- Refractive index
- 1.674 – 1.77
- Surface relief
- High
- Principal indices
- nω 1.674 · nε 1.77
- Pleochroism
- Weak
Crystallography
- Space group
- #10
- Cell parameters
- a = 12.329(2) Å · b = 7.11 Å · c = 18.741(2) Å
- Cell angles
- β = 102.68(1) °
- Ratio a:b:c
- 1 : 0.577 : 1.520
- Z
- 12
- Morphology
Acute pyramidal; spindle-shaped. Also thin or thick tabular.
- Twinning
On (0001)
- Comment
Strongly pseudohexagonal. Commonly observed subcell is primitive-hexagonal, a ~4.10, c ~18.2 A.
Chemical composition
Synonyms
- IMA1982-030
- Synchisit-(Ce)
- Synchisite-(Ce)
- Synchysiet-(Ce)
In other languages
- French
- Synchysite- · Synchysite-(Ce)
- German
- IMA 1982-030 · Synchysit-(Ce)
- Spanish
- Sinchisita- · sinchisita-(Ce)
- Italian
- Synchysite- · Synchysite-(Ce)
- Chinese
- 直碳鈣鈰礦
Classification
5.BD.20c
- 5CarbonatesClass
- 5.BCarbonates with additional anions, without H2ODivision
- 5.BDWith rare earth elements (REE)Group
- 5.BD.20cSynchysite-(Ce)Species
16a.01.03.01
- 16aAnhydrous Carbonates Containing Hydroxyl or HalogenClass
- 16a.01(AB)(XO3)ZqType
- 16a.01.03Synchysite SubgroupGroup
- 16a.01.03.01Synchysite-(Ce)Species
12.1.13
- 12Carbonates with other anionsClass
- 12.1Carbonates with halidesGroup
- 12.1.13Synchysite-(Ce)Species
Group, growth & confusion
Literature, links & citation
- 1900Flink, G. (1900): Mineralogische Notizen. 1. Ueber den Synchysit von Narsarsuk in Süd-Grönland, ein Mineral, welches für Parisit gehalten wurde. Bulletin of the Geological Instution of the University of Upsala, 5, 81-87.
- 1966Levinson, A. A. (1966) A system of nomenclature for rare-earth minerals. American Mineralogist, 51 (1-2) 152-158
- 1987Nickel, Ernest H., Mandarino, Joseph A. (1987) Procedures involving the IMA Commission on New Minerals and Mineral Names and guidelines on mineral nomenclature. American Mineralogist, 72 (9-10) 1031-1042
- 1993Ni, Yunxiang, Hughes, John M., Mariano, Anthony N. (1993) The atomic arrangement of bastnäsite-(Ce), Ce(CO3)F, and structural elements of synchysite-(Ce), röntgenite-(Ce), and parisite-(Ce) American Mineralogist, 78 (3-4) 415-418
- 1994Wang, L., Ni, Y., Hughes, J.M., Bayliss, P., Drexler, J.W. (1994): The atomic arrangement of synchysite-(Ce), CeCaF(CO3)2. The Canadian Mineralogist, 32, 865-871.
@misc{mineral2026,
author = {Mineral Index editorial board},
title = {Synchysite-(Ce) — Mineral Index},
year = {2026},
url = {https://mineralindex.org/minerals/synchysite-ce-3853},
note = {Accessed 2026-05-11}
}