Art Deco Onyx and Diamond Hat Pin by Cartier
This Cartier Diamond and Onyx Hat Pin screams Art Deco. The juxtaposition of black and white with the onyx and diamonds is typical from this era. Additionally, the strong lines of the pyramid top allude to the ever popular 1920s. The top pyramid of onyx seems to show minor sunbleaching, likely from it's use atop a gentleman's hat!