Iol Gem

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

In-game description
"Iol is actually short for Iolite (cordierite), although a common nickname is "violet stone" even though its overall hue is usually blue. Iols are usually cut into faceted gems to best display the stone's color change as it is viewed from different directions. Small, cut iols can be clear, but larger specimens usually contain silky inclusions of another substance such as hemitite crystals, which give the same rich golden flash of color as in sunstones."