Water Opal

Water Opals are 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
"Water Opal is a colourless, clear opal with a play of colour. It is rare and valuable in the Realms, where it is used in scrying devices."