Hi Kathy thanks for writing in and congratulations on your Akoya pearl necklace.
Akoya pearls are what usually come to mind when people describe a pearl necklace strand. Akoya pearls are produced by the Pinctada Martensii also known as the Pinctada Fucata - be careful how you pronounce that ;-)
Akoya pearls, the finest Akoyas pearls that is, have the highest luster of all types of pearls and are more perfectly round than other types of pearls. Unfortunately, for girls who like big pearls, Akoya pearls rarely exceed 10 millimeters in diameter and when they do they command exceptionally high prices.
Originally Akoya pearls were only cultured in Japan but now China is a major producer of Akoya Pearls.