4mm genuine black diamond set in 18k gold signet ring. The table of the ring measures at about 6mm x 14mm. The Diamond is hand set in a low profile bezel to mimic the subdials on a matching chronograph watch. The original design was inspired by the great Omega Speedmaster 321 in Canopus Gold, but has been further designed to match the golds of the moonwatch professionals. Can be made with other colored diamonds or sapphires by request. Alternate finger sizing is available.