The coin is an authentic tetradrachm made of silver. We are not stating any purity for the coin since ancient coins vary in purity by region. Sadly this seems too common on items that are difficult to authenticate due to poor training or lack of care. Items with coatings are often failed. Items that are mixed metals often don't pass.All of our diamonds are genuine and none of our gold is plated (unless otherwise noted). We test all diamonds and gold before listing. All jewelry items are pre-owned unless otherwise stated. This means they have the usual aspects of pre-owned jewelry, such as light scratches, wear and tarnish. If there is a major dent, ding, flaw, or bend, it will be noted in the description.