Tomb jade

Tomb Jade was the name for jade that had been buried for centuries and turned from green to red or brown.

Description
Tomb jade was rare and commanded a high price in the Realms. Normal jade was considered a fancy stone, but after being mined and possibly worked, then buried for great lengths of time, it changed color and was worth ten times as much. A typical specimen had a base value of 1,000 gp. Note that jade turned green if buried with items made of bronze which rendered it equivalent in value to normal jade.

Powers
Powdered tomb jade was an ingredient in potions of undead control. It could also be used as a talisman for turning undead, granting a priest a second chance to turn an undead creature after a failed attempt.