VII.—On the Occureence of Albite in the Granite of Leinster

Extract

During the past summer, I had the good fortune to detect Albite (Soda-feldspar) in some blocks of granite in the wall of the west pier at Kingstown, Co. Dublin. As the pier is built of rock from the Dalkey quarries, the mineral can be referred, with tolerable certainty, to its original locality. I was induced to look closely at the above-mentioned blocks, through noticing that they contained a mineral of a purple colour; this proved to be fluor, which occurs sparingly throughout the Leinster granite. Associated with the fluor was a pretty considerable quantity of a white mineral, occurring in aggregations of minute crystals; this appeared to me to be so like Albite that I considered it deserving a careful examination.