Pearl with a mother of pearl bead center. In the cultured pearl industry, the resources used to create a mistaken all nacre baroque pearl is a drain on the production of round cultured pearls. Therefore, they are trying to improve culturing technique so that keshi pearls do not occur. All nacre pearls may one day be limited to natural found pearls. Today many "keshi" pearls are actually intentional, with post-harvest shells returned to the water to regenerate a pearl in the existing pearl sac. Tahitian pearls, frequently referred to as black pearls, are highly valued because of their rarity; the culturing
The Pearl of Death when caught the pearl is not found on him and he is released. Later, Holmes hears of an apparently motiveless murder. An elderly colonel is found with his back broken amid a pile of smashed china. Holmes takes an immediate interest in the case as the unusual method of killing is that of "The Hoxton Creeper" (Rondo Hatton), known to be Conover's right-hand man. Another murder occurs, of a little old lady, also surrounded by smashed china. Conover makes two attempts to kill Holmes, who surmises that Conover is desperately trying to recover the stolen pearl. After a third killing