Charles I (1625-49) silver Pattern Half Groat. 

CAR . D . G . MAG . BRIT . FRAN . ET . HI . R . (diamond), bare-headed bust right in ruffled collar.
FIDEI . DEFENSOR ., crown above two interlocked Cs, .B. below. 

Seaby 2856A. North 2687. Also known in copper.
Courtesy Ira & Larry Goldberg Auctioneers, Beverly Hills, CA. www.goldbergcoins.com
Sale 31: The Pre-Long Beach Auction May 30 - June 1, 2005, Lot 2165.