Maybe there's an IT tribologist out there that will refute me, but there's no such thing as a "pure" synthetic in the dictionary sense of the word pure- they all have a little bit of dinosaur in them to carry the synthetic particles. They use the word "pure" when the dinosaur is below a legally-defined limit (kinda like fat-free corn chips that have something like 0.05% fat and the government set a limit on what "fat-free" meant). When you get above that limit of dino, they call it a blend, like Syntec does.