Helicon
Helicon was a silver-coloured mineral that was not highly valued. Its low conductivity and strength meant that demand for commercial or industrial use was also low, though it was commonly used in pipes. However, helicon could be "activated" by an individual with certain psychic abilities, in which state it could be used to record the brain patterns of said individual. When this was done the individual would live on within the helicon itself.
Xais instructed Menlove Stokes, whose job it was to create portraits of inmates at the Rock of Judgement before their execution, to use helicon to cast a death mask of her. Three years after her execution, still alive within the helicon mask, she gained enough strength to force Margo, the Rock's chief of security, to wear her mask and subject herself to be taken over by Xais. (PROSE: The Romance of Crime, AUDIO: The Romance of Crime)
