Jargoon

Jargoon was a rare variety of zircon found in the Realms.

Description
Jargoons were valued for their resemblance to deep red rubies in color and luster. A typical specimen had a base value of 100 gp.

Powers
One powerful use of this gemstone was as a magic missile enhancer. The caster held a jargoon in a hand and cast magic missile through it. This caused the jargoon to explode, but the number of missiles was doubled with no alteration in targets, damage, range, etc. The drawback was that the explosion damaged the caster's hand as if struck by a single particularly strong magic missile.

Rumors and Legends
An unproven legend stated that a jargoon could prevent a lycanthrope from changing out of human form.