Hi Rokor:
Sorry, I'm a bit late to this party. I'm not sure about that Miki clasp. Also, the pearls don't look that great.
I'm not sure about Sea Magic. I have a strand of Blue Lagoon that belonged to my Aunt Love. This was another of the less expensive Mikimoto brands, and the pearls look amazing, but small (6 mm).
Personally, I've been thrilled with the Hanadamas with certificates I bought from Pearl Paradise. And Pearls of Joy also has amazing Hanadamas, too. Plus, both have generous return policies, so I've returned pearls that weren't to my liking. Both are are online vendors and they want you to be happy or they will accept returns. That's their business model. An Ebay or other purchase of a used necklace may not allow returns.