How do I find the fourth gem? I collected in the fort, in Witton and in the castle Deminius. After taking the white gemstone from the book in the Deminius castle, there is no more hints.
Locations of the gems:
1. Tajurata Fort -> Second floor -> Shelf in the top left. (unlocks gem 3)
2. Jewelry Store in Thremten (unlocks gem 4)
3. Magic store in Witton (unlocks gem 5)
4. Yin Tower otuside (Fight against some bandits)
5. Diminus Castle (Guy in a small house)
6. House of the priester in Old Ashton (requires that you have all 5 other gems first and then talk with Aiyana.)