“Old cassiterite specimen in the mineral collection of Museu Alfredo Bensaúde, IST Lisbon; estimated field of view 15 cm. This pegmatite formation initially formed three mine shafts with the technical name, attributed by Direcção Geral de Minas - (DGM), "Mina de Chão de Castanheiro" (Chão de Castanheiro mine, actually Cubos mine). Rui Nunes' photo, January 2017.”