Originally Posted by player1
"Perl + armor" formula is missing. You can create this way more valuable armor too sell.

It also applies to some other things. Works with bracers and helmets (but not all helmets, hasn't worked on cloth cap).

It's not missing, it's formulated as a more generic formula:
[Crafting 1] Boosted Apparel = Apparel + Pearl (The Adventurer's Field Guide VII) (+ Gold Value)