What about the white crystal? Is it still a drop? It used to be from Ulgo Siegebreaker but clearly that's changed because no one can get it to drop.
The Magenta Crystal does in fact exist, but it is not acquired through Reverse Engineering. At the present time, it could be classified as one of the rarest items in the game.
While I am not going to give any more information on how, where or from whom it may be acquired, I want to debunk the idea that you have to reverse engineer endgame gear to get it so people don't do stuff they regret.