Spanish: Openwork that is done after a coin has been issued is a handicraft or numismatic jewelry. A pierced coin or medal with the openings being part of its design. Production openwork calls for a piercing die on a punch press. Many of the highest ranking military decorations are pierced for emphasis. This is rarely done because of the high costs so it gives these medals an exclusivity.
Source: Numiscadero Spanish to English Glossary (Gary Beals)