Biotite granite igneous rock specimens from Ballachulish, Scotland, UK. Composed of the felsic minerals quartz and feldspar, with occurrences of biotite crystals. The rock has an overall white appearance due to its felsic chemistry but the black biotite mica offers a striking contrast in colours. The samples are ideal for both collectors due to the attractive nature and for college to university level education to describe the variations in granite which one may find. The samples are available in three sizes and supplied in a card tray with an information label.