Physics and Chemistry of Minerals

, Volume 3, Issue 2, pp 117–131 | Cite as

Color centers, associated rare-earth ions and the origin of coloration in natural fluorites

  • H. Bill
  • G. Calas
Article

Abstract

Natural colored fluorites were studied by means of optical absorption and electron paramagnetic resonance (EPR). Complex centers involving rare-earth ions and/or oxygen give rise to the various colors observed. These include yttrium-associated F centers (blue), coexisting yttrium and cerium-associated F centers (yellowish-green), the (YO2) center (rose) and the O 3 molecule ion (yellow). Divalent rare-earth ions also contribute to the colorations, as for instance Sm3+ (green fluorites), or they are at the origin of strong fluorescence observed (Eu2+). Strong irradiation of the crystals with ionizing radiation leads to coagulation of color centers, and to precipitation of metallic calcium colloids. There is probably no simple relation connecting the coloration and the growth process of the crystal. Thermal stability studies, however, have allowed to partially classify the colors as being of primary or secondary origin.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Abragam, A., Bleaney, B.: Electron Paramagnetic Resonance of Transition Ions. Oxford: Clarendon Press, 1970Google Scholar
  2. Alig, R.C.: Theory of photochromic centers in CaF2. Phys. Rev. B 3, 536–545 (1971)Google Scholar
  3. Alig, R.C., Kiss, Z.J., Brown, J.P., McClure, D.S.: Energy levels of Ce2+ in CaF2. Phys. Rev. 186, 276–284 (1969)Google Scholar
  4. Bailey, A.D., Hunt, R.P., Taylor, K.N.R.: An ESR study of natural fluorite containing manganese impurities. Mineral. Mag. 39, 705–708 (1974)Google Scholar
  5. Baker, J.M., Hurrell, J.P.: Fluorine electron nuclear double resonance (ENDOR) in calcium fluoride. Proc. Phys. Soc. 82, 742–756 (1963)Google Scholar
  6. Baker, J.M., Williams, F.I.B.: Electron nuclear double resonance of the divalent europium ion. Proc. Roy. Soc. (London) 276 A, 283–294 (1962)Google Scholar
  7. Beaumont, J.H., Harmer, A.L., Hayes, W.: The F3 centre in alkaline earth fluorites. J. Phys. C. Solid State Phys. 5, 257–265 (1972)Google Scholar
  8. Bill, H.: Investigation of colour centres in alkaline earth fluorides. Helv. Phys. Acta 42, 771–797 (1969a)Google Scholar
  9. Bill, H.: ENDOR investigations of Gd3+ in CaF2 crystals. Phys. Rev. Letters 29 A, 593–594 (1969b)Google Scholar
  10. Bill, H.: Resolved electron-phonon interaction observed in the optical absorption spectrum of a color center in calcium fluoride. In: Magnetic Resonance and Related Phenomena. Proc. Congr. AMPERE 16th 1971, pp. 529–532Google Scholar
  11. Bill, H., Lacroix, R.: Investigation of different centres in CaF2 crystals. In: Magnetic Resonance and Relaxation. Proc. Congr. AMPERE 14th 1967, pp. 262–268Google Scholar
  12. Bill, H., Mareda, J.: ENDOR investigation of a V Fcenter in natural CaF2 crystals. Chem. Phys. Letters 36, 218–221 (1975)Google Scholar
  13. Bill, H., Sierro, J., Lacroix, R.: Origin of coloration in some fluorites. Am. Miner. 52, 1003–1008 (1967)Google Scholar
  14. Bill, H., Osten, W. Von der: Raman and vibronic spectra of a new oxygen molecule ion in CaF2. Phys. Status Solidi (B) 75, 613–619 (1976)Google Scholar
  15. Bontinck, W.: The hydrolysis of solid CaF2. Physica 24, 650–658 (1958)Google Scholar
  16. Braithwaite, R.S.W., Flowers, W.T., Hazeldine, R.N., Russel, M.: The cause of the colour of Blue John and other purple fluorites. Mineral. Mag. 39, 401–411 (1973)Google Scholar
  17. Calas, G.: Etude de la coloration bleue de quelques fluorites naturelles. Bull. Soc. Franc. Minéral. Crist. 95, 470–474 (1972)Google Scholar
  18. Calas, G., Curien, H., Farge, Y., Maury, R.: Cinétique de guérison des centres colorés de la fluorite jaune de Valzergues (Averyron). Principe d'un thermomètre géologique. C.R. Acad. Sci. (Paris) 274, 781–784 (1972)Google Scholar
  19. Calas, G., Huc, A.Y., Pajot, B.: Utilisation de la spectrophotométrie infrarouge pour l'étude des inclusions fluides des minéraux: intérêts et limites. Bull. Soc. Franc. Minéral. Crist. 99, 153–161 (1976)Google Scholar
  20. Calas, G., Touray, J.C.: An upper limit for the crystallization temperature of yellow fluorites (with special reference to the thermal bleaching of samples from Valzergues, France). Mod. Geol. 3, 209–210 (1972)Google Scholar
  21. Calas, G., Zarka, A.: Etude des défauts de croissance dans des monocristaux de fluorite naturelle. Bull. Soc. Franc. Minéral. Crist. 96, 274–277 (1973)Google Scholar
  22. Feofilov, P.P.: Absorption and luminescence of bivalent ions of rare-earth elements in natural and synthetic fluorite crystals. Opt. Spektr. 1, 992–999 (1956)Google Scholar
  23. Görlich, P., Karras, H., Kötitz, G., Rauch, R.: Polarized luminescence of X-irradiated CaF2: Y and SrF2: Y crystals and the structure of their luminescence centres. Phys. Status Solidi 27, 109–115 (1968)Google Scholar
  24. Goldberg, I.S.: Color of fluorite from the Takob deposit (Hissar range). Geochem. Int. 1, 1103–1106 (1963)Google Scholar
  25. Guichard, F.: Contribution à l'étude de la distribution des lanthanides dans la barytine. Thesis, Paris University (1974)Google Scholar
  26. Hayes, W. (Ed.): Crystals with the Fluorite Structure; Electronic, Vibrational and Defect Properties. Oxford: Oxford University Press, 1974Google Scholar
  27. Hayes, W., Twidell, J.W.: Paramagnetic resonance of X-irradiated CaF2: Tm and CaF2: Yb. J. Chem. Phys. 35, 1521–1522 (1961)Google Scholar
  28. Holgate, N.: Dichroic pigment-layers in Blue John fluorite. Mineral. Mag. 39, 363–366 (1973)Google Scholar
  29. Hunt, G.R., Salisbury, J.W., Lenhoff, C.J.: Visible and near-infrared spectra of minerals and rocks. V: Halides, phosphates, arseniates, vanadates and borates. Mod. Geol. 3, 121–132 (1972)Google Scholar
  30. Jones, G.D., Peled, S., Rosenwaks, R., Yatsin, S.: Spectra of hydrogenated calcium fluoride containing rare-earth ions. Phys. Rev. 183, 353–368 (1969)Google Scholar
  31. Kubo, K.: Effects of proton bombardment on CaF2 crystals. J. Phys. Soc. Japan 21, 1300–1303 (1966)Google Scholar
  32. Loh, E.: 4f n −1 5d spectra of rare-earth ions in crystals. Phys. Rev. 175, 533–536 (1968)Google Scholar
  33. Loh, E.: Ultraviolet-absorption spectra of europium and ytterbium in alkaline earth fluorides. Phys. Rev. 184, 348–352 (1969)Google Scholar
  34. Low, W.: Paramagnetic resonance spectrum of trivalent gadolinium in the cubic field of calcium fluoride. Phys. Rev. 109, 265–271 (1958)Google Scholar
  35. MacKenzie, K.J.D., Green, J.M.: The cause of coloration in Derbyshire Blue John banded fluorite and other blue banded fluorites. Mineral. Mag. 38, 459–470 (1971)Google Scholar
  36. Manthey, W.J.: Crystal field and site symmetry of trivalent cerium ions in CaF2: the C 4V and C 3V centers with interstitial fluoride charge compensator. Phys. Rev. B8, 4086–4098 (1973)Google Scholar
  37. Marchand, L., Joseph, D., Touray, J.C., Treuil, M.: Critères d'analyse géochimique des gisements de fluorine basés sur l'étude de la distribution des lanthanides-application au gîte de Maine (71 Cordesse, France). Minér. Deposita 11, 357–379 (1976)Google Scholar
  38. McLaughlan, S.D., Evans, H.W.: Production of colloïdal calcium by electron irradiation of CaF2 crystals. Phys. Status Solidi 27, 695–700 (1968)Google Scholar
  39. O'Connor, J.R., Chen, J.H.: Color centers in alkaline earth fluorides. Phys. Rev. 120, 1790–1791 (1960)Google Scholar
  40. Przibram, K.: Verfärbung und Lumineszenz — Beiträge zur Mineralphysik. Wien: Springer 1953Google Scholar
  41. Recker, K., Neuhaus, A., Leckebusch, R.: Vergleichende Untersuchungen der Farb- und Lumineszenzeigenschaften natürlicher und gezüchteter definiert dotierter Fluorite. Proc. I.M.A. Cambridge, 145–152 (1968)Google Scholar
  42. Ryter, C.: Résonance paramagnétique dans la bande de 10.000 mC/s de l'europium et du gadolinium soumis à un champ cristallin cubique. Helv. Phys. Acta. 30, 353–373 (1957)Google Scholar
  43. Sierro, J., Lacroix, R.: Résonance de l'ion Gd3+ dans les fluorines avec compensation de charge. C.R. Acad. Sci. (Paris) 250, 2686–2687 (1960)Google Scholar
  44. Staebler, D.L.: Optical studies of a rare-earth F center complex in rare-earth doped calcium fluoride. Ph.D. Thesis, Princeton (1969)Google Scholar
  45. Staebler, D.L., Schnatterly, S.E.: Optical studies of a photochromic color center in rare-earth doped CaF2. Phys. Rev. B3, 516–526 (1971)Google Scholar
  46. Vinokurov, V.M., Zapirov, M.M., Pol'skii, Yu.E., Stepanov, V.G., Chirkin, G.K., Shekun, L.Ya.: Electron paramagnetic resonance determination of trace amounts of Eu2+, Gd3+ and Nb4+ and their isomorphism in fluorite and zircon. Geochim. Int. 1, 1041–1046 (1963)Google Scholar
  47. Vochten, R.F.C., Geys, J.F.: Solid inclusions in a fluorite variety from the Wölsendorfer Range (Bavaria, Fed. Rep. Germany). Schweiz. Mineral. Petrogr. Mitt. 57, 23–30 (1977)Google Scholar
  48. Weakliem, H.A.: Electronic interactions in the 4f 6 5d configuration of Eu2+ in crystals. Phys. Rev. B6, 2743–2748 (1972)Google Scholar
  49. Weber, M.J., Bierig, R.W.: Paramagnetic resonance and relaxation of trivalent rare-earth ions in calcium fluoride. I. Resonance spectra and crystal fields. Phys. Rev. 134, A 1492–1503 (1964)Google Scholar

Copyright information

© Springer-Verlag 1978

Authors and Affiliations

  • H. Bill
    • 1
  • G. Calas
    • 2
  1. 1.Départment de Chimie PhysiqueUniversité de GenèveGeneve 4Switzerland
  2. 2.Laboratoire de Minéralogie-Cristallographie, associé au C.N.R.S.Université Pierre et Marie CurieParis Cedex 05France

Personalised recommendations