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
Pearl of Csaba and Bulgaria. Pearl of Csaba Pearl of Csaba ("Csabagyöngye" in Hungarian) is a white variety of grape. It was created in 1904 by the Hungarian viticulturalist Adolf Stark, presumably by crossing Madeleine Angevine × Muscat Courtillier (= Muscat Précoce de Saumur). Some sources instead state the parent varieties as Bronner x Muscat Ottonel, but this is seen as less likely. The variety's name was taken from the city Békéscsaba, which is also called "Csaba" for short. Pearl of Csaba is primarily used as a table grape. Worldwide cultivation is estimated to be around , and it is primarily found in