Chardalyn (pronounced: CHAR-dah-lin) is a rare, naturally occurring substance mined in nugget form in the northern and northwestern regions of Faerûn.
When first discovered in Netheril, these oval-shaped black stones were described as "useless rocks" by miners, but their affinity for magic was soon discovered.
The nuggets were as brittle as glass and turned into a powder when they were forcefully struck or when hurled against a solid object.
A single chardalyn nugget could absorb one spell, which was released when the stone was crushed or destroyed. This was a natural ability of the substance and did not require any magical preparation or treatment beforehand. The spell stayed encased in the chardalyn indefinitely—it could be released seconds or centuries later.
Usually, the spell was cast with the chardalyn as the target and it was absorbed without fail, but an empty chardalyn had a slightly better than even chance to absorb a spell that did not target it directly, as long as it was in the spell's area of effect.
Once a chardalyn was imbued with a spell, additional spells had no effect on the stone.