Synthetic pearl nucleus and its manufacturing method null for cultivation pearl

摘要

PURPOSE: To obtain synthetic pearl nuclei sufficiently prevented from the possibility of e.g. pearl elimination in pearl culture as the case with synthetic pearl nuclei having been conventionally proposed, thereby enabling high-quality pearls to be produced. CONSTITUTION: The objective synthetic pearl nuclei, with a bulk density of 2.5-2.9g/cm3 and water absorption of =3wt.%, consists of a sintered compact obtained by baking a raw material comprising 95.0-99.5wt.% of carbonate compound(s) consisting of calcium carbonate and/or magnesium carbonate and 0.5-5.0wt.% of a lithium compound. The synthetic pearl nuclei can be obtained by molding the raw material followed by baking at =525 deg.C but 900 deg.C under carbon dioxide partial pressure and then conducting an abrasive finishing. The synthetic pearl nuclei thus obtained is excellent in surface appearance, hue and gloss and also biocompatibility with the shells used in pearl culture, therefore being adequately usable as decorative pearls. Besides, the pearl nuclei can be stably and easily produced, and their sintering form can also be easily controlled.