The present samples are from the Wicklow mountains where the quartz is white. In Donegal granite, the quartz has an admixture of iron and therefore a pinkish-red appearance

Below: the piece de resistance: a rare photograph of an event that took place 400 Million years ago. A vein of granite squeezes through a convoluted crack in the older mica schist. (Brown Mountain, Co, Wicklow)

Further below: detail of granite composition.