Igneous rubble stone used in Malvern and around the Malvern Hills. A variety of lithologies make up the Malvern Hills of which diorite and tonalite (intermediate between granite and basalts) are the most common. Granites, pegmatites, dolerites, basalts and ultramfic lithologies also occur. Many of the rocks have been sheared and altered by fault movement, particularly south of the Wyche, giving them the appearence of high-grade metamorphic rocks. These are less used for building however as they tend to be more fissile. Owing to the highly fractured nature of the rock, it is almost impossible to produce dimension stone leading to the distinctive random rubble style of construction of Malvern buildings.
A great number of quarry operated in the hills, mostly extracting rock for aggregate but also for building. The last of these, Tank Quarry on North Hills, ceased to operate in the 1970s.