agete Black Opal Earrings Materials: Silver x Black Opal Post: K10 Opal size: Approximately 4mm in diameter Purchased from agete FOR MEN. I love the beautiful colors, but I'm selling it because I no longer use it as a single earring. The black opal's brilliance changes with the angle, making it very mysterious. The post is K10, so you can wear it with confidence. *The post is slightly bent, and the price reflects this. *Cleaned. No box or warranty card.