Ice sapphire

Ice sapphires were enchanted sapphires found in the plane of Ysgard that protected against cold.

Description
These crystals had a deep blue coloration and inner light, though once their magical effect was used this inner light faded. They were notably always cool to the touch. Their value was significantly diminished after use.

Powers
Ice sapphires granted their wielder the power to make a single, powerful casting of endure cold.

History
In the, a group of adventurers from the city of Ravens Bluff on the world of Toril traveled to Ysgard in search of the legendary Well of Mimir. While traveling in Asgard, they stopped at the hall of Gloamingard at the same time as the Seelie Court was visiting. Queen Titania, desiring some entertainment, challenged the adventurers to a series of friendly competitions against her fey entourage. For their trouble she offered as prizes an ice sapphire, a Svartalfheim cloak, and a horn of Valhalla.