A Silica Animus is an artificial mind (rather than a simple Cogitator) created from forbidden technologies and is considered, perhaps, the greatest sin in the Cult Mechanicus and is a terrible crime under Imperial law. Tradition holds that such unholy constructs are inherently evil and a perverted abomination in the sight of Omnissiah. Adeptus Mechanicus religious doctrine states that the Machine Spirit of a Silica Animus is a twisted mockery of the soul of man, treacherous and insane. Ancient texts tell apocryphal stories, shrouded in metaphor, of such murderous and powerful creations during the Dark Age of Technology, and the legions of "Iron Men" that served them, blaming them in part for many of the terrible wars that laid humanity low in that lost time and brought on the Age of Strife.
- Dark Heresy - Disciples of the Dark Gods (RPG), pg. 44
- The Horus Heresy - Book Two: Massacre (Imperial Armour) by Alan Bligh, pg. 264