Cameo Pendant/Brooch of Flora, the Roman goddess of spring and flowers.

This cameo of Flora, the Roman goddess of spring and flowers dates from the Art Deco period circa 1920–1925 and was originally sold in the USA.

It has an unusual combination of 14k white gold (latticework frame)and yellow gold (brooch fastener and hinged bail on the back) framing its delicate shell carving.  

Why is this from the 1920s? Here are the clues:

•The "14K" mark is stamped on the hinge of the safety flip-lock on the back, a popular mechanism in the 20s.

•The specific typeface and placement for the mark also became popular in American jewelry during the 1920s.

• White gold was invented as a popular substitute for platinum in the 1910s and boomed in popularity during the 1920s. 

• The "openwork" latticework style of the frame became popular during this time.

• Cameos shifted in style from classical Roman features in Victorian cameos to softer Greek-influenced features during this decade.