This item belonged to my mother and is from a while ago. It's a K18 Mexican opal ring. It features a raw opal (water opal?), diamonds, emeralds, and rubies. The size is approximately size 12, and it weighs 8.42g (please allow for slight variations). The hallmarks are K18, Opal 5.13, and Diamond 020. I've lost the grading report, but the other stones were emeralds and rubies (there are no hallmarks for these). I recently had the opportunity to visit a jewelry store, and they mentioned that opals are currently difficult to obtain, and rings with this kind of volume are also rare. The ring also uses a generous amount of gold (apparently, the price of gold has risen recently, making it too expensive to use a lot of gold. It's also difficult to get new stock, and sales are slow due to the high prices). The back of the ring is solid, so it doesn't snag, and it feels very smooth on the finger. The opal has the characteristic play of color, displaying beautiful orange and green hues when viewed from different angles. While there are some signs of wear from normal use, it's still in good condition and can be enjoyed. The original case is not included. It will be shipped in a different case via Yamato Takkyubin Compact. Please understand that this is a used item and has been stored at home. Thank you.