Euclase

Euclase was a rare precious stone found in the form of small crystals.

Description
Euclase was easily cut into faceted gems and came in various colors ranging from colorless to pale yellow, vivid yellow, pale green, and blue. The blue hues commanded the highest price. A typical specimen had a base value of 500 gp.

Powers
These gemstones had a dangerous and violet reaction to magic being cast upon them or upon a being wearing or carrying one. If successfully hit with a spell, a flame strike erupted from the euclase, destroying it in the process and damaging any creature or object in the area of effect.