A Gold color metal and enamel device 1 1/8 inches (2.86 cm) in height overall consisting of a shield blazoned: Dark Purple, a pair of rifles in saltire Or, in chief a passion cross of the last. Attached above the shield, a Gold scroll inscribed "CD" in Dark Purple letters. Attached below the shield, a Gold triparted scroll inscribed "RELIGIO MORES CULTURA" in Purple letters. Which translate to: obligations to God, the community, and to the ancestors and descendents.
Gold and blue are the school colors. The letters "CD" refers to the school' name derived from the two founding partners of the school; Bishop Cretin and Mr. Hugh Derham. The gold represents the four virtues of nobleness, goodwill, vigor and magnanimity. The dark purple symbolizes leadership, trustworthiness, wisdom, dignity, independence, creativity, loyalty and sincerity.
The shoulder loop insignia was authorized 12 April 2011.