The lavas exploited as ornamental and construction rocks in the region of Clermont-Ferrand, as in Besse-et-Sainte-Anastaise, come from volcanic eruptions. They are extracted from the cooled flows of the Chaîne des Puys' volcanoes. The most widespread lava rocks are black and compact basalts and purplish-gray andesites that result from lava flows or explosive volcanism. Numerous buildings of the region are also made from light gray trachytes, such as the famous Volvic lava.