Rough Diamond can be found in Boulders and in Natural Island Treasure Caches and Desert Island Treasure Caches, and randomly when digging up these caches while wielding the Treasure Hunter's Shovel. They can sometimes be sold by merchants.
The only ways to increase Stamina Regeneration in Salt are by:
- Nightvigor Flower Potion - (Adds 5 Stamina Regen for 10 mins)
- Seaweed Extract - (Adds 3 Stamina Regen for 10 mins)
- Diamond Ring - (1 Stamina Regen, passive)