2x diamonds
 

I also have a JC enc that can do the combines if you so desire (and provide materials); no guarantees of success.

I'm not exactly sure what they are worth on red - I miss the auction tracker - but I saw one guy offering 8k for a diamond mask a month ago so maybe something in that range. Also would consider trades for: NoS, Tranix Crown, Shiny Robe of the Underfoot, Goblin Gazughi Ring, Bracer of the Hidden, or if you are really, really desperate a Hierophant's Cloak.