Malacon

Malacon was a variety of zircon found in the Realms.

Description
These semi-precious stones could produce large brown faceted gems that were hard but fragile, so they were not generally used in jewelry that was frequently subject to impact, like rings,  but they were often used in room decorations. A typical specimen had a base value of 50 gp.

Powers
Malacon gems could be used to store a spell and release it at a later time, making them ideal for pranks, surprises, defenses, or death traps to those who knew the modifications necessary to cast a spell into this gem. The spell could be released in one of three ways: by physically breaking the gem, either by striking, dropping, or crushing; by the caster touching the gem and exerting his or her will to call forth the spell; or when a predetermined interval, set during the original casting of the spell, had passed. In the first case, the caster had no control of the spell, it went off with the gem as the origin or center of the spell. In the second case, the caster had full control of the spell as if he or she had just cast it from memory. In the third case, all the spell's characteristics, including the time delay interval, were fixed and unchangeable at the time the spell was cast into the malacon. In all cases, the gemstone was destroyed or harmlessly vaporized when the stored spell was triggered. It was possible for someone other than the caster to take control of a spell stored in a malacon, but it required great skill in the use of very specialized spells.