Production. Majorica pearls are not formed in mollusks, but are man-made on solid glass balls coated with layers of pigmented and protective lacquers. They begin from high density dull glass with a specific weight, similar to that of real pearls.
Keshi pearls are small non-nucleated pearls typically formed as by-products ofpearl cultivation. A Japanese word also meaning "poppy" (ケシ, 芥子), it is used in Japanese for all pearls that grew without a nucleus. ... Because they have no nucleus, keshi pearls are composed entirely of nacre.