Horn Coral Gem

Horn Coral Gems 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
"Horn Coral, which is also called night coral, is a deep black coral, similar to angel's skin save for its solid color. It is incredibly difficult to work with, and is used in jewelry as a polished twig or branch of material, or is cut cabochon."

Baldur's Gate II: Shadows of Amn
Limited Wish can create Horn Coral Gem.