FOR THE GREEEEEEEEEEEEN
Amalgamated Gemstone Forging
From what I read, it works with any of the rare crests so long as you have 3 of each = 1 pile of dust.
I’ve heard that you can also substitute the Crests with Orbs (although you can’t mix Crests and Orbs in the same MF attempt). So it’s either 3 × 3 × 3 Crests, or 3 × 3 × 3 Orbs.