The entire body of this instrument was pure white and covered with intricate pearl carvings. The base, or soundbox, was actually made from a single giant pearl taken from one of the giant clams of the Crowded Sea. Since collecting the giant pearl was a dangerous task, the marids wisely had lesser beings perform this task.
This 'ud allowed the user to cast a strong charm person spell when the instrument was played. Bards and rawunin could use this power twice per day, but all others could only access this magic once per day.
Only bards and rawunin could "raise the waters" when playing the 'ud of the marids, summoning a powerful water elemental to do their bidding. This power could only be used once per week and the 'ud needed to be near a sufficient supply of water in order for the magic to function. The elemental remained under control so long as the 'ud was played but instantly returned to their home plane if the music was interrupted or ceased altogether.