Buy crystal or entity, although it is more expensive (bargain! ), but rest assured.
I really want to buy something around 580 in JD.COM, and I must buy something with an appraisal certificate! (that's the kind of personal certificate)
The crystal photos on the Internet must be polished (shiny), and absolute jewelry will not be reflected without polishing.
You'd better take a picture to see if you want to buy a pendant, bracelet or necklace.