China Jiuquan Night-Shining Cup This is a traditional Chinese craft item, the Jiuquan Night-Shining Cup (yakouhai). Size: Diameter: Drinking rim: 6cm Base: 5cm Height: 10cm The genuine Night-Shining Cup is made by hollowing out a rare stone mined in the Western Regions of China. Inferior products are reportedly made by molding stone scraps (powder). The way to tell them apart is that a genuine one will be attracted to a magnet, while an inferior product made of powder will not react. I read that. I tried bringing a magnet close to it, and it reacted. It appears to be unused. There are no stains or scratches. It comes in a cosmetic box, but the box is dirty. It has been stored at home for a long time. Please refrain from purchasing if you are sensitive to such things.