Kuaru's Prize is a ring in Pillars of Eternity II: Deadfire.
When the volcano erupted on the far side of the island, Paoraw Aoaha - the ranga of the local Huana tribe - ordered the Roparu shorewalkers to scour the lava fields in search of valuable volcanic ash to fertilize the crops. While performing this duty, one shorewalker came about a small, white jewel resting atop the surface of a cooling lava pool. She carefully retrieved it.
She took the gem to the village artisan - a Kuaru who occasionally dealt with the lower caste - and asked him to make a ring with the stone so she could properly present it to the ranga. The Kuaru recognized the gem as a piece of the heart of the volcano. It was a prize beyond the station of the Roparu, and the ranga surely would not appreciate its true value. He confiscated the jewel and sent the shorewalker away. He crafted a ring but had no intention of parting with it.