Riddick collection No. 04 – Summary of a rare plaquette reproducing the classical “Felix Gem,” probably cast in Rome under the auspices of Pietro Barbo (future Pope Paul II).
Riddick collection No. 07 – Summary of a rare plaquette reproducing the head of a satyr, being a freehand copy after an antique or contemporaneous carved gem.
Riddick collection No. 17 – Summary of a rarely discussed plaquette of Asclepius, reproducing an antique gem probably belonging to the Medici in Florence.