This coin could be 90% silver, but the giveaway is the reverse, has a reverse of 79+, when all 78 CC had the 78 CC reverse. Also he has a 79 CC that looks kinda suspicious but cant confirm, need more experienced eyes. https://www.ebay.com/itm/1878-CC-Carson-City-Mint-Silver-Morgan-Dollar-Clear-CC-Silver-Coin/174556885182?hash=item28a466b0be:g:S8gAAOSwjkhf1TAj
A lady (?) tried to sell me one about 8 years ago. Just took pictures with my digital camera. Told her I’d get back to her. A week later she called me asking if I had the money to buy it. She really went off the rails when I told her it was a well known counterfeit. Should have offered bullion value Pretty sure it was silver
Some are 50% silver from old British Coins being melted Think Hong Kong The weight difference gives them away