The book spells out the recipe , verbatim. Noxcium, a Celaeno fragment... and a third elder resource you'll need to determine :) the right result will create the piece. the wrong might create another entirely. Or nothing at all. But yea, stick with strictly "elder" resource drops. That should at least get you lookin in the right place. You'll need something non-euclidian.

I tried with ''non-euclidian'' elder item before but only yielded the piece of the ''elder'' armor. Is this recipe for that set? or there is an another set called horrid?
Please tell me there is another one :)

no, each piece of the set has a *different* recipe. But yes, there is a whole set.