Abstract: The rare zeolite mineral gobbinsite has been found in vugs of altered basalts at the Magheramorne Quarry, Lane, Northern Ireland, intimately associated with phillipsite. The crystal chemistry of the sample (Na_4.3Ca_0.6Si_10.4Al_5.6O₃₂·12H₂O) is close to that reported for gobbinsite from the type locality. The crystal structure of the Magheramorne gobbinsite has been refined from X-ray powder diffraction data using the multiphase Rietveld full profile technique. The orthorhombic Pmn2₁ space group is confirmed. The refined cell parameters (a = 10.1027(5), b = 9.8016(5), and c = 10.1682(6) Å) are slightly different from those reported in the literature for the K-rich gobbinsite from Island Magee (a = 10.108(1), b = 9.766(1), and c = 10.171(1) Å), whose structure was also refined from powder data.