Augite andesite igneous rock specimens from Thirlmere, Cumbria, UK which are of late Ordovician age which form part of the Barrowdale volcanic group. The samples are of intermediate composition and contain phenocrysts of the pyroxene mineral, augite, giving the normally dark blue rock a black speckled appearance. The samples are available in 3 sizes and come supplied in a card tray with a label.