This normal-seeming pearl will radiate a faint dweomer of the Enchantment sort if magic is detected for. In any event, the stone will be very beautiful and worth at least 1,000 gp on this basis alone. 

If it is clasped firmly in hand or to breast and the possessor attempts actions related to any of the pearl's power areas, he or she will understand and be able to employ the item. 

The pearl enables its possessor to breathe in water as if he or she were in clean, fresh air. 

Underwater movement rate is 24". 

The possessor is also immune to any ill effects from the touch of a sirine. 

The pearl must be within the general area of the possessor—less than 1" distant—to convey its powers to him or her.