Vintage Mikimoto pearls do have silver clasps - I have three, so I'm not questioning that (originally purchased by my father in the mid to late 50's in Japan). It's the blue pearls that surprised me for being Mikimoto vintage. I did not know that Mikimoto sold blue akoya pearls before 1962-64. I'm a Mikimoto collector (and pearl collector in general) and have many of their pieces, but never seen vintage blue akoya.