I purchased a Mikimoto pearl strand years ago and would like to find out more info. Or what might worth? It is 18" in length and pearls size are 6 1/2 x 7 mm. On the certificate, it said Exquisite Cultured Pearls. Division of Mikimoto (America) Co, Ltd. There is a marking on the clasp said 14kt BL. Is it possible BL stands for Blue Lagoon? Thanks in advance!