Stranakelly Prospect, County Wicklow

This rock crystallized from granitic fluids over 400 million years ago. The large crystals, which in some cases are over 30cm in length, are one of the characteristic features of a pegmatite.

The long bladed crystals within this pegmatite are composed of the lithium mineral spodumene. Spodumene is one of the main sources of the element lithium and this pegmatite comes from one of a number of lithium mining prospects found along the margins of the Blackstairs Mountains in counties Carlow and Wicklow.

These pegmatites also contain small crystals of minerals that are rich in valuable rare metals such tantalum (Ta) and niobium (Nb).