Liroconite crystals. 19th-century illustration of a specimen of crystals of the mineral liroconite, with details of crystal geometry below the specimen. This mineral is a form of hydrated copper aluminium arsenate hydroxide. The specimen shown here is from Wheal Gorland, Cornwall, UK. This artwork, dated 1803, is from 'British Mineralogy', issued between 1802 and 1817 by British naturalist James Sowerby (1757-1822).