Lead, copper, zinc, barite, haematite, tungsten, graphite, fluorite, and coal have all been mined at different times since as early as the 12th century.
en.wikipedia.org Dark red haematite is usually the last surviving pigment, unless a painting is subject to floodwaters or other physical agents.
theconversation.com There are also some other small unmined mineral veins, such as ankerite, molybdenite and haematite.
en.wikipedia.org A 2005 work has shown that the slip is a matrix of mainly silicon and aluminium oxides, within which are suspended sub-microscopic crystals of haematite and corrundum.
en.wikipedia.org The soil here is red due to haematite and climbing lore suggests that magnetic compasses can not be trusted in this locality.
en.wikipedia.org