To judge the standard of genuine silver bricks, there must be eight documents, including: 13% VAT invoice, ex-factory quality certificate, ex-factory code list, registered trademark certificate, business license, legal representative ID card, Shanghai Gold Exchange registration certificate (London Gold and Silver Market Certification Certificate) and enterprise account number. In addition There are also two kinds of steel seals, the pure steel seal of refinery trademark number and the steel seal of seller's trademark.