Star Stones are a currency in Spirit Stones. They are used in Transforming. They can be obtained by selling Rare, Super Rare, and Ultra Rare cards. As well as gold, Star Stones of a color corresponding with the card's class (red for Warrior, blue for Mage, etc.) are received upon the sale.
- Rare cards made from N+++ sell for 2 Star Stones.
(I tried its with Hesta a Rare 4 star card, this gave 2 Star Stones aswell; Eas a Rare 5 star card also gave 2 Star stones - thus it's probably safe to say all Rare cards sell for 2 Star Stones.)
- Rare+ cards made from the N+++ cards sell for 3 Star Stones.
- The Super Rare cards made with these Rare+ cards (like: Giant Warriot, Hell Raider, Sniper, Shaman, Knight Commander, Pyromancer, Ninja and Demon blader) sell for 5 Star Stones of their respective class.
Concluding from this chart, it's wisest to sell the Rare cards if you're trying to collect Star stones. Don't evolve them any further.