This evening gown and coat, made of silk moire dates from 1967.  The dress is sleeveless and ankle length, with a thin self belt and asymetrical buttons down the back. The coat is double breasted, and trimmed in black mink at the cuffs and collar. The sleeves are elbow length and would have been worn with gloves that were opera (or elbow) length.
Photos courtesy of The Museum of the City of New York.