Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-27T06:59:47.970Z Has data issue: false hasContentIssue false

The cause of the colour of Blue John and other purple fluorites

Published online by Cambridge University Press:  05 July 2018

R. S. W. Braithwaite
Affiliation:
Department of Chemistry, University of Manchester Institute of Science and Technology
W. T. Flowers
Affiliation:
Department of Chemistry, University of Manchester Institute of Science and Technology
R. N. Haszeldine
Affiliation:
Department of Chemistry, University of Manchester Institute of Science and Technology
M. Russell
Affiliation:
Department of Chemistry, University of Manchester Institute of Science and Technology

Summary

‘Blue John’ andother purple fluorites have been studied by a wide range of techniques. Hydrocarbons are not the cause of the colour of these fluorites. No significant difference in the concentrations of 73 elements between the purple and colourless zones of Blue John has been detected. The spectroscopic and thermal bleaching behaviour of the purple zones is consistent with the presence of ‘colloidal’ calcium as colouring agent, and coloration of fluorites with calcium vapour gives material showing similar properties. The distribution of colour suggests trapping of the calcium in lattice defects along {111} (cleavage) planes through {001} (growth) zones. The ‘colloids’ could be produced by aggregation of calcium atoms liberated by irradiation from sources found in the geological environment of Blue John. The banding could arise from variations in the concentration of lattice defects caused by variations in growth rates of the fluorite.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1973

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Allen, (R. D.), 1952. Amer. Min., 37, 910-30.Google Scholar
Barnes, (J.) and Holroyi, (W. F.), 1896. Trans. Manchester Geol. Soe., 24, 215-53.Google Scholar
Beaumont, (J. H.), Harmer, (A. L.), and Hayes, (W.), 1972a. Journ. Physics, C, 5, 257-65.CrossRefGoogle Scholar
Beaumont, (J. H.), Harmer, (A. L.), and Hayes, (W.), 1972b. Ibid. 1475-88.Google Scholar
Beaumont, (J. H.), Harmer, (A. L.), and Hayes, (W.) and Spray, (A. R. L.), 1972. ibid. 1489-1500.CrossRefGoogle Scholar
Bettinali, (C.), 1959. Atti (Rendiconti) Acad. Lincei, 26, 777-8.Google Scholar
Bill, (H.), Sierro, (J.), and Lacroix, (R.), I967. Amer. Min., 52, 1003-8.Google Scholar
Blanchard, (F. N.), 1966. Amer. Min., 51, 474-85. 1967. Ibid. 52, 371-9.Google Scholar
Blournt, (B.) and Sequmra, (J. H.), 1919. Trans. Chem. Soc., 115, 705-9.CrossRefGoogle Scholar
Bontrnck, (W.), I958. Physica., 24, 639-49.CrossRefGoogle Scholar
Calas, (G.), 1972. Min. Mag., 38, 977-9.CrossRefGoogle Scholar
Cornu, (A.) and Massot, (R.), Compilation of Mass Spectral Data Heyden and Son, London.Google Scholar
Coscrove, (M. E.) in Ramsbotrom, (W. H. C.), Rhys, (G. H.), and Smith, (E. C.), 1962. Bull. Geol. Surv. Great Britain, 19, 75-168, p. 164.Google Scholar
Doelter, (C.), 1925. Tschermaks Min. Pert. Mitt., 38, 456-63.Google Scholar
Dunham, (K. C.), 1952. Special Reports on the Mineral Resources of Great Britain, Geological Survey 4, Fluorspar. H.M.S.O.Google Scholar
Evans, (W. D.), Cooper, (B. S.), and Gunn, (R. K.), 1964. Internat. Series Monographs Earth Sci., 15 Advances in Organic Geochem. 1962, Pergamon Press, 417-21.Google Scholar
Font, (F. K.) and Yokom, (P. N.), 1964. Journ. Chem. Phys., 41, 1383-8.Google Scholar
Garnett, (C. S.), 192O. Trans. Chem. Soc., 117, 620-2.CrossRefGoogle Scholar
Gobel, (L.), 1930. Sitz. Akad. Wiss. Wien, Abt. 1, 139, 373-91.Google Scholar
Gobel, (L.) 1931. Zeits. Krist., 76, 457-8.Google Scholar
Hayes, (W.), Lambourn, (R. F.), and Smith, (P. H. S.), 1970. Journ. Physics, C, 3, 1797–;1805.CrossRefGoogle Scholar
Hill, (J. J.) and Aron, (J.), 1953. Journ. Chem. Phys., 21, 223-8.CrossRefGoogle Scholar
Holgate, (N.), 1941. Ph.D. Thesis, University of Manchester 139-48.Google Scholar
Holgate, (N.) 1973. Min. Mag., 39, 363-6.CrossRefGoogle Scholar
Kittel, (C.), 1968. Introduction to Solid State Physics. New York.Google Scholar
Krantz, (R. L.), 1968. Trans. lnst. Mining Met. Sect. B. 778, 26–;36.Google Scholar
Lisitsyna, (L. A.), 1965. Optics and Spectroscopy, 19, 167-8.Google Scholar
Lüty, (F.), 1953. Zeits. Phys., 134, 593-603.CrossRefGoogle Scholar
Mackenzie, (K. J. D.) and Green, (J. M.), 1971. Min. Mag., 38, 459-70.CrossRefGoogle Scholar
Mackenzie, (K. J. D.) and Green, (J. M.) 1972. Min. Mag., 38, 979-81.CrossRefGoogle Scholar
Mclaughlan, (S. D.) and Evans, (H. W.), 1968. Phys. Stat. Solidi, 27, 695-70o.CrossRefGoogle Scholar
Mayerl, (M.), 1951. Sitz. Akad. Wiss. Wien, Abt. lla, 160, 31.Google Scholar
Messner, (D.) and Smakula, (A.), 196o. Phys. Rev., Series 2, 120, 1162-6.Google Scholar
Mollwo, (E.), 1934. Nachr. Ges. Wiss. G6ttingen, Fachgruppe 2, 1, 79-89.Google Scholar
Mueller, (G.), 1954. Cong. Geol. Internat. Compt. Rend. i)me Sess., Algdrie, 15, 523-39.Google Scholar
Mueller, (G.) Recke, (G. W.), and Vera Mege, (R.), 1961. Bol. Soc. Chilena Quim., Concepcion, Chile December, 8–;12.Google Scholar
Peacock, (J. D.) and Taylor, (K.), 1966. Bull. Geol. Surv. Great Britain, 25, 19–;32.Google Scholar
Ponsford, (D. R. A.), 1955. Bull. Geol. Surv. Great Britain, 10, 22-4.Google Scholar
Przmram, (K.), I938. Nature, 141, 970.CrossRefGoogle Scholar
Rao, (D. R.) and Bose, (H. N.), 1970. Journ. Phys. Soc. Japan, 28, 152-7.CrossRefGoogle Scholar
Scouler, (W. J.) and Smakula, (A.), 1960. Phys. Rev., Series, 2, 120, I I 54-6I.Google Scholar
Simpson, (I. M.) and Broadnurst, (F. M.), I969. Proc. Yorks. Geol. Soc., 37, I4I-5I.Google Scholar
Smakula, (A.), I95O. Phys. Rev., Series, 2, 77, 4o8-9.Google Scholar
Smakula, (A.) I953. Phys. Rev., Series 2, 91, 1570-1.Google Scholar
Stevenson, (I. P.) and Gaunt, (G. D.), 1971. Mem. Geol. Surv. Great Britain, Geology of the Country around Chapel en le Frith 164. H.M.S.O.Google Scholar
Van Doorn (C. Z.), , 1961-2. Phillips Res. Rep. Suppl. Google Scholar
Wohler, (L.) and Kasarnowski, (H.), I9o5. Zeits. anorg. Chem., 47, 353-70.CrossRefGoogle Scholar