"Koshidama" (over-year pearls) and "Koshimono" (over-year items) are specialized terms in the pearl industry. Typically, pearls are cultivated for a year to allow the nacre to form. Pearls harvested in the usual one-year period are called "Tonenmono" (this year's items). Koshidama, on the other hand, are cultivated for longer than a year, resulting in impressive pearls. The thickness of the nacre is about 0.2 microns per layer, and exceeding 2,000 layers results in a thick nacre, exceeding 0.4 mm. Based on pearl standards, Koshimono are generally thick-nacre and of high quality. Koshidama are cultivated for over a year, and the harvesting timing is also done during the cold months of October to February. Pearls harvested after January, when the cold becomes more intense, tend to have a beautiful finish because the final layer is tightly and finely wound, like the rings of a tree. There are Koshimono harvested in February, 16 months after the October start of the Tonenmono, and Koshidama harvested in February, 28 months later. Naturally, thick-nacre pearls are resistant to aging and last longer, so they are recommended. Size: Approximately 6.5-7mm Length: Approximately 41cm (including clasp) Pearl Shape: Round Metal Fittings: Stamped SILVER Condition: In beautiful condition, so it is an item that can still be used for a long time. Accessories: Case #IshinLux Full Pearl Necklace * Pearls and natural stones may have minor natural imperfections. We take photos as close to the actual product as possible, but the appearance may vary depending on the device. Please check the product description and photos carefully before purchasing. We do not accept returns or exchanges due to differences in image. Shipping Process Inspection → Determination of good quality → Disinfection → Carefully packaging each item (basic simple packaging with bubble wrap + envelope) → Anonymous shipping