Celestine

Nothing in this list is craftable in turn, so one Celestine is a single step: 12 units of material drawn from 2 base items, plus 2 crystals.

That bill outweighs 6,221 of the 13,602 recipes tracked here and 862 of the 2,216 Goldsmith ones, and 9,374 recipes nest deeper.

None of the 2 raw materials do not appear in the gathering data, so the whole bill comes from vendors, drops or content this site does not track.

Celestine is itself consumed by 11 further recipes, spanning two of the eight crafting classes.