So, fun fact. In the 1940s, the US tariffs on cultured pearls was 200% for finished strands - and 10% on unfinished strands. So jewelry stores on military bases would sell pearls, and then sell the clasps separately. But the clasps couldn’t be stored in the box when it went through customs. So the owner of this 3.5 momme strand still might find a little paper bag, or blue and clear plastic pouch with a Mikimoto clasp in it
One of the biggest problems in the pearl market is that the average person has no idea what a pearl is, and the value of it. Even the average jeweler or gemologist struggles know the difference between a $1k strand and a $11k. Mikimoto has gotten around this by having consistent clasps, and the clasp is considered to be a guarantee of standards. Of course, that means that there is a market just for Mikimoto clasps. And for Mikimoto boxes.
Which brings us to the crux of the issue.
The market for 3.5 momme strands has grown tremendously in the last decade. Bless GenZ and their thrifty, dainty, retro-loving hearts. But “grown tremendously” is a relative term. Ten years ago, a 3.5 on a silver clasp sold for about $10-20. Even Miki was $50 to 125. Today, a generic 3.5 momme is about $75 to $200, and a Mikimoto is $300-600. A loose undamaged midcentury Mikimoto clasp is currently averaging about $150 to $400.
Collectors and historians love paperwork and provenance, so the seal, and the stamp, and the receipt and box means that this will sell on the upper end of generic ($200-350ish) but someone who wants to wear it (and cares about the paperwork) will want the matching clasp, and the future buyer does need to think about that.