Frost agate

Frost agate, also called frost stone, was a beautiful member of the agate family found in the Realms.

Description
These rare ornamental stones were had white markings that resembled frost over the base color of the stone. They were usually tumbled and polished to a beautiful glassy finish. A master lapidarist could cut the fragile stone in facets, such as in a polyhedron cut, so that at each point where facets met, a "snowflake" of white "frost" appeared. A typical stone had a base value of 10 gp.

Powers
Frost agates were often enchanted to be luckstones. Low quality stones were treated like other agates: powdered for use in sleeping draughts and other potions. Frost agate in particular was useful when mixing potions together as it nearly always prevented an explosive or poisonous result.