AN EXCEPTIONALLY LARGE CRYSTAL SKULL, late 19th/early 20th century, Brazil, an impressive crystal skull of exceptional size, hand-carved from a single block of rock crystal (quartz), 20cm high 26cm deep The crystal skulls of Meso- and South America emerged as revered artefacts in the mid-19th century, when they were often alleged to be of Pre-Columbian or even extraterrestrial origin. However, several studies carried out by the British Museum, among others, concluded these to have been impossible creations without the aid of rotary tools, tools which were not conceived until the mid-19th century.