Pearl Necklace Info and Identification

Came to possess a 14 inch strand if pearls. Clasp marked 14k IWA. Nacre thick, pearls white. Took strand to local jeweler....he found the IWA mark, told me he was confident that pearls were saltwater, and called the pearls "potato pearls". They are not perfectly round but roundish. Want to know what IWA stands for....pearls are in a Friedman's Jeweler's box.