Stoneheart

Stoneheart is used to create the reagent Blood Spawn. Stoneheart essentially is a reddish rock that is crushed and the powder mixed with human blood to create Blood Spawn. It is forbidden, though most mages in Serpent Isle have some hidden away.

In Moonshade, Stoneheart can only be possessed with the permission of the Magelord. Prolonged exposure to stoneheart causes uncontrollable fits and insanity. The Mountains of Freedom were sealed when Stoneheart was found within, but some few mages still voluntarily enter the mountains in an attempt to get Stoneheart. Stoneheart can also be found in the Skullcrusher Mountains.

In Ultima VII Part Two, the Avatar managed to gain possession of Stoneheart when a teleport storm exchanged Rudyom's Wand with Stoneheart from Skullcrusher. Its importance for spellcasting however would remain unclear until the mage Ensorcio at the Inn of the Sleeping Bull revealed it after being offered a big enough sum. On the other hand, Pothos in Moonshade was tasked with pulling all Stoneheart out of circulation, when asked.

Trivia

 * Vasculio worked with Stoneheart.