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.
Also to me this screams that it's in a hard to reach place yet out in the world like the white node is. Otherwise he'd have just told us it dropped from a boss as the challenge then would be in getting to and killing said boss and getting it to drop. The distinct lack of info here seems to hint that if he told you anything, it would spoil the challenge.
Time to bust out our collective maps, compasses, and backpacks guys. We've got exploring to do.