Turquoise Gem

Turquoise Gems are very valuable gems in the game which may be found. This item appears in Baldur's Gate (game), Baldur's Gate: Enhanced Edition, Baldur's Gate II: Shadows of Amn and Baldur's Gate II: Enhanced Edition.

In-game description
"Turquoise is an opaque aqua stone with darker mottling, and is found in the more arid reaches of the Realms. Horsemen will often place a sliver of this stone in a horse's harness as a sign of good luck."

Baldur's Gate II: Shadows of Amn
Limited Wish can create emerald.