Diamond in the Rough

Diamond in the Rough is a Tome of Knowledge Bestiary entry for Troll, Stone.

Instructions: Order & Destruction

Kill "Boulder Chukkas" on the hill above Duraz Dok, until you get a Pocket Item "Consumed Rough Diamond". Equip it for the unlock.

Once the unlock triggered, you can claim the jewel buying it from the correct merchant in Library (Order) / Lyceum (Destruction).

Just east of them, you will find a Chaos Troll "Vragi the Brute" for Brutal Nose Ring unlock.