Chabazite (var. Phacolite)

A specimen of chabazite (var. phacolite) from Clinty Quarry, County Antrim, Northern Ireland, showing numerous small crystals scattered across an elongated vug in basalt matrix. The crystals are colourless and measure only a few millimetres in size, displaying the characteristic twinned habit typical of phacolite. Though modest in scale, the crystals are well formed, gemmy, and provide a pleasing example of zeolite mineralization within the vesicular basalt.

Clinty Quarry exposes flows of the Antrim Plateau Basalts, part of the extensive Paleogene volcanic province that dominates much of County Antrim. Vesicles within the basalt were later filled by mineral-rich fluids, producing a wide range of zeolite minerals including chabazite, thomsonite, mesolite, and others. Specimens such as this represent classic zeolite material from the basalt quarries of Northern Ireland, where small cavities can yield delicate crystallized minerals.