Vintage Silk and Sequined Slip Maxi Dress

STUNNING sheath, slip, whatever you want to call it. Given to me by my sister-in-law 30 years ago. I never wore it and it has been kept in this plastic bag, wrapped in tissue paper this whole time. Black silk with iridescent sequins. Wear it with or without the belt. I like it without. The way it fits the mannequin, I would say it's a size 6. Label reads a medium. No flaws anywhere. Mint condition.