Spinel

The precious stone spinel was not native to North Faerûn. Spinels came to the region from traders with the Southwest and from visitors to Kara-Tur.

Description
Red spinels were said to come from southern desert country, while blue spinels came from the east, and the rare green spinels came from the jungles of Chult and Mhair. All types were transparent or translucent and durable. A typical blue specimen had a base value of 500 gp  while the red to green shades were valued at around 100 gp.

Powers
If a spinel was crushed in a particular way and then ingested, a spellcasting creature could instantly remember (and recast) the last spell cast.