Specimens of augite andesite found in Thirlmere, Cumbria, UK. Specimens are supplied in a white card tray with a information label. Andesite is an extrusive rock intermediate in composition between rhyolite and basalt. It is the volcanic equivalent of Diorite with a silica comtent of 52-63% plus pyroxene ( Augite) & feldspars (Plagioclase) which are someimes large enough to occur as phenocrysts. Andesite lava is of moderate viscosity and forms thick lava flows and domes. These particular specimens of andesite contain augite crystals which can be clearly seen.