Evening gown ca. 1920s. Black silk georgette column with V-neck & V-back in chevron/stripe swag pattern of crystal, white, & rhinestone beading. Banded neckline and right hip medallions and looped scalloped fringe below knee over gathered chiffon flounce. Hook & eye closures on both shoulders.
Here is an exemplar of Deco geometric design. The dress was fashioned from sheer black silk chiffon that was later lined for support. This makes it wearable and saves you the trouble of finding the right slip. I believe the chiffon hem flounce was added when the dress was lined.