Synthetic Alizarin Lake. This is a less commonly listed variation of Alizarin Crimson, however artiscreation.com posits that perhaps actually it is this variety that is often found in tubes labeled PR83.
A similar health warning to that on PR83 would likely apply here. Though it is a lesser-known hazard, chemically, both artificial and natural alizarins are actually incredibly similar to cancer-causing anthraquinones. It may also cause allergies. Monona Rossol's work on pigments contains more information.
