Cacoxenite

A very rich specimen of the rare hydrated aluminum–iron phosphate cacoxenite from County Limerick, Ireland. The piece displays numerous tiny radial clusters of acicular crystals forming delicate fan-shaped rosettes across the matrix. The crystals exhibit the bright golden-yellow colour characteristic of this species, creating an attractive contrast against the quartz-pebble conglomerate host rock. Although individual crystals are minute, the dense coverage and colour make this a particularly eye-catching example.

Cacoxenite is an uncommon mineral worldwide and is especially rare from Irish localities. This material comes from the Fort Lismeenagh area, where small boulders and limited exposures occur along a stream bank and bed at the edge of Ballycormick townland. The name “Fort Lismeenagh” refers to a nearby prehistoric earthwork. Fine specimens such as this, showing well-developed golden rosettes, represent excellent examples of this scarce Irish phosphate mineral. From the international collection of Robert Yeoman.