Hogan Bolas Vintage Enamel Copper Earrings

Mid Century Modernist enamel copper earrings. Vintage Circa 1950 by Hogan-Bolas. Early 50's perhaps. Enamel on copper. Modernist design by Robert Hogan & Deborah Bolas who operated a jewelry business in Rhode Island circa mid-century. Rich reflective colors of  green and blue with some white .   They are oval 1" x .75".  The condition is good for age.  Thy copper has taken on a dark patina.