George Washington Portrait Cameo, circa 1875
Shell, 2 3/32 inches (5.31 cm.) oval, collection of SGNHS

To create a cameo design in shell, great care must be taken not to crack the brittle medium. The shell's outer layer must first be removed with a file. The design is cut into the second layer of shell, and the third or colored layer serves as a contrasting background. 

Mary Queen of Scots Cameo, Williams Version, 1873
Onyx, 1 7/16 inches (3.65 cm.), collection of SGNHS

This version of the Mary Queen of Scots Cameo was commissioned by Abigail Williams, a painter and student in Rome. She was a friend of Augusta Homer, Saint-Gaudens’ fiancée and later wife. In 1874, Saint-Gaudens cut a now-lost Mary Queen of Scots Cameo as an engagement present for Augusta Homer. The cameo, mounted as a ring, is thought to be the last cut by the sculptor.