Calico Stone

The Calico Stone was a residuum-infused astral diamond. It was famous throughout history as a magical focus, priceless artifact, and treasure beyond compare. The Calico Stone was used by many spellcasters, including Mordenkainen, St. Lionni, and Armentarius the Transmuter.

In the Green Timeline, it was used by Keela the dragon to summon Vecna to the Material Plane.

In the Median Timeline, the Calico Stone was lost after powering the Null-blocking divine shield around the city of Vyetka. It resurfaced over 2,000 years later in the Light Age, being a treasure of the Kingdom of Trigonon.