If you have access to Stoneheart Castle, you will receive daily Tasks where you can clear Stoneheart Trials of different levels to get powerful Rewards! Go to the "Stoneheart" tab in your Eagle's Nest to find these Tasks.
Earn Stoneheart Scrolls or Adamantine by completing them. Note that you will need to actively discover Stoneheart Masteries to access the Stoneheart Scrolls.