GOBBINSITE FROM MAGHERAMORNE QUARRY, NORTHERN-IRELAND

The rare zeolite mineral gobbinsite has been found in vugs of altered basalts at the Magheramorne Quarry, Lame, Northern Ireland, intimately associated with phillipsite. The crystal chemistry of the sample (Na4 .3Ca0.6Si10.4Al5.6O32.12H(2)O) is close to that reported for gobbinsit e from the type locality. The crystal structure of the Magheramorne go bbinsite has been refined from X-ray powder diffraction data using the multiphase Rietveld full profile technique. The orthorhombic Pmn2(1) space group is confirmed. The refined cell parameters (a = 10.1027(5), b = 9.8016(5), and c = 10.1682(6) Angstrom) are slightly different fr om those reported in the literature for the K-rich gobbinsite from Isl and Magee (a = 10.108(1), b = 9.766(1), and c = 10.171(1) Angstrom), w hose structure was also refined from powder data.