This is a 1902-S Morgan Dollar in an MS-65 Paramount International Redfield holder.
The LaVere Redfield hoard of 400,000 coins, mostly mint condition, was found sealed behind a false wall in his basement.
The bachelor Redfield had lived near Reno for more than 70 years and hoarded these coins. After his death, the county court disposed of the hoard at an auction in 1976 for more than $7 million. The successful bidder split the hoard among several dealers.
These pieces, later encased in small, red plastic holders, are known simply as "Redfield dollars."