Marble

Marble is a type of metamorphic stone, most commonly found as calcite or dolomite. It is usually white, and is most commonly used for decorative purposes. Marble is known specifically for not being used in traps. However, it has been theorized that marble may in be used as traps in very rare circumstances, to trick unsuspecting adventurers who assume it is not trapped.

History
The Temple of Bahamut in Venya, the Layer of Pearls in Mount Celestia was built primarily of marble.