Apophyllite, Gyrolite, Thomsonite

A classic basalt vug specimen from the Maxwell Quarries, County Londonderry, Northern Ireland, displaying an attractive association of zeolite minerals. The cavity is lined with delicate crystals of apophyllite accompanied by gyrolite and thomsonite, forming a pleasing mineral assemblage typical of zeolite-rich basalt cavities.

Maxwell Quarries lie along the western margin of the Antrim Plateau Basalts, a vast Paleogene volcanic province in Northern Ireland famous for its zeolite mineralization. Vesicles within the basalt flows were later filled by hydrothermal fluids, giving rise to a variety of zeolite species including chabazite, apophyllite, gyrolite, and thomsonite. Specimens such as this represent classic material from one of Ireland’s best-known localities for zeolite minerals.