I'm a seller. I'm a buyer. The actual grading system is dependent on the type of item being graded.
Authentication is a way of determining whether an item is genuine and described appropriately.
Because of their training and experience, experts can often detect counterfeits from subtle details. However, you should know that two expert authenticators may differ on the authenticity of the same item. I'm a seller . Sellers can boost bidder confidence by having items pre-authenticated by an independent authenticator before listing an item. Sellers can promote the fact that an independent expert has approved the item which will let bidders know that the item has been examined by a highly qualified, experienced professional who has pledged to provide an unbiased opinion.