Crown of silver

Crown of silver was the Realms name for psilomelane chalcedony, a variety of chalcedony containing many fine bands of black manganese.

Description
The black bands of these ornamental stones took on a brilliant polish alongside the silver chalcedony, so crown of silver was usually sliced for inlays, tumbled smooth, or cut cabochon. A typical stone had a base value of 10 gp.

Powers
In powdered form, crown of silver had a mundane use in preventing rust on ferrous metals when applied directly. In magic, it was used as a component of the (possibly mythical ) everbright spell. It could also be used in place of iron filings in most spells that required them, such as certain protection spells.

Reputation
Crown of silver was a common stone among the drow, a gem worn by drow of average station.

The lesser deity of the drow Vhaeraun was known to occasionally send crowns of silver to show his favour or disfavour to his followers.