The coin was salvaged from the wreck site of the Concepcion which sank in July, 1641 at the Silver Shoals, off the Dominican Republic. There is an information sheet about the Concepcion, but I do not have a Certificate of Authenticity for this coin. It weighs 26.5 grams and is 1.5 in diameter. The item "Spanish Mexico Spanish Colonial 8 Reales Cob Coin 1630-1641" is in sale since Monday, December 30, 2019. This item is in the category "Coins & Paper Money\Coins\ World\North & Central America\Mexico\Colonial (up to 1821)". The seller is "waramaug11" and is located in New York, New York. This item can be shipped worldwide.