Sterling Silver and Onyx Ring, Margaret De Patta, c. 1950s, designed as a rotating onyx disk within a shaped frame, size 7, maker's mark, signed. Note: De Patta (1903-1964) was a modernist studio jeweler from San Francisco and a prominent figure in the mid-century art jewelry movement. She adhered to Constructivist principles of form and structure in her work, which consists of rectangular planes, interplay of light and shadow, and moving elements. De Patta's jewelry was selected for the 1946 show at the Museum of Modern Art "Modern Handmade Jewlery", which also included work by Calder and Lipchitz. The exhibition highlighted "wearable art as a movement in America". Her work is owned by the Smithsonian, the British Museum, and the MFA Boston.