the proper koetsu name for the diamond version of the jade platinum is the "burma jade." i own a burma jade and have compared it in my system and my dealer's to the onyx and jade platinums, which are the same cartridges but for the body material. the burma jade is quite clearly within the sound "style" of the other upper eschelon stone-bodied koetsus but takes that style several steps beyond. its musicality and detail are so perfectly combined that it suffers nothing in comparison to the highest end insiders, lyras or the like. i can't recommend it too highly.
associated equipment: clearaudio anniversary, with synchro, outer ring, etc; graham phantom; aesthetix io signature phono; boulder pre and nagra vpa's.