Gatelite-(Ce) mineral
Cerium-dominant calcium-aluminum-magnesium-iron epidote-tornebohmite polysomatic silicate mineral with current September 2026 IMA-CNMNC approved formula (Ca,Ce)4(Al,Mg,Fe)4(Si2O7)(SiO4)3(O,F,OH)3 (ideal structural formula (CaCe3)(Al3Mg)[Si2O7][SiO4]3O(OH)2), status A, and approval number IMA 2001-050. Bonazzi, Bindi, and Parodi (2003) described the holotype specimen (MNHM 201.228, Museum National d'Histoire Naturelle, Paris, with the structure crystal at the Museo di Storia Naturale, Universita di Firenze) from dolomitic horizons of the Trimouns talc deposit, 6 km north of Luzenac, Ariege, French Pyrenees, France, where it occurs in cavities lined with dolomite and parsingite/allanite-(Ce) alongside quartz, calcite, talc, thorianite, hingganite-(Y), iimoriite-(Y), bastnasite-(Ce), synchysite-(Ce), parisite-(Ce), monazite-(Ce), aeschynite-(Y), and dissakisite-(Ce) (growing parallel to gatelite-(Ce) with a1 and c1 of gatelite-(Ce) parallel to c and a of dissakisite-(Ce)). Electron-microprobe WDS analysis (mean of 6 point analyses, Table 1, p. 224) with H2O derived from crystal-structure hydrogen-bonding and charge balance yielded SiO2 28.105, Al2O3 14.435, FeO 2.133, MgO 1.910, CaO 5.660, La2O3 8.170, Ce2O3 20.580, Pr2O3 2.215, Nd2O3 11.740, Sm2O3 1.755, Dy2O3 0.150, Y2O3 0.370, Nb2O5 0.075, F 0.245, less O=F 0.103, anhydrous sum 97.440 wt% (total 98.780 wt% including 1.34 wt% H2Ocalc), corresponding on the basis of 13 cations per formula unit to the empirical formula (Ca1.09La0.54Ce1.36Pr0.14Nd0.75Sm0.11Dy0.01Y0.04)Sigma4.04(Al3.06Mg0.51Fe2+0.32Nb0.01)Sigma3.90Si5.06O20.26(OH)1.60F0.14. Single-crystal X-ray diffraction refined in monoclinic space group P21/a (a = 17.770(4), b = 5.651(1), c = 17.458(4) A, beta = 116.18(2) degrees, V = 1573.3(6) A3, Z = 4, Robs = 4.65% for 4997 reflections with Fo > 4sigma(Fo) and R = 7.15% for all 6891 independent reflections, Dcalc = 4.51 g/cm3, ncalc = 1.807, Mohs hardness 6-7; Tables 2-6, pp. 225-228) established an regular ET polysome alternating (001) epidote-type (E) and (-102) tornebohmite-type (T) structural modules. Distinct from dissakisite-(Ce), allanite-(Ce), tornebohmite-(Ce), vastervikite, and elemental cerium, lanthanum, or neodymium; no criticality designation, microbial mechanism, or industrial recovery yield is asserted.
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Identifiers & Classification
| System | Identifier | Label |
|---|---|---|
| IMA |
IMA:2001-050
|
Gatelite-(Ce) |
Sources & References
-
ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026, PDF page 80, Gatelite-(Ce) row: formula (Ca,Ce)4(Al,Mg,Fe)4(Si2O7)(SiO4)3(O,F,OH)3, status A, IMA No. 2001-050, country France, reference American Mineralogist 88 (2003), 223; column definitions on PDF page 1.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-23) -
bonazzi_2003_gatelite: Bonazzi P, Bindi L, Parodi GC (2003), Gatelite-(Ce), a new REE-bearing mineral from Trimouns, French Pyrenees: Crystal structure and polysomatic relationships with epidote and tornebohmite-(Ce), American Mineralogist 88:223-228. Complete 6-page primary PDF visually inspected: Trimouns dolomitic horizon occurrence, holotype MNHM 201.228, and EMPA composition Table 1 pp. 223-224; Gandolfi powder XRD Table 2 and monoclinic P21/a ET-polysome crystal-structure refinement Tables 3-6 and Figures 2-5 pp. 224-228.
https://www.rruff.net/doclib/am/vol88/AM88_223.pdf (accessed 2026-10-23)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-23T07:15:00Z |
antigravity | CREATE | Created gatelite-(Ce) mineral record with verified IMA:2001-050 identity, Trimouns holotype MNHM 201.228 EMPA chemistry, and monoclinic P21/a epidote-tornebohmite ET-polysome crystal structure from the complete 2003 primary study. |
Record source: data/records/gatelite-ce.yaml