From DariaWiki

Witchblock is the most common alternate term/name used for Terrestrial Salazarium. While the metal was known to many Native American tribes for centuries beforehand (particularly among the tribes in the areas that correspond to the modern-day U.S. western states that border Canada), it was first used by North American settlers and colonists in the late 17th Century. Its first known use came around the time of the infamous Salem Witch Trials.