3D Floral Embroidered Long Sequin Prom Dress Dresses Purple Floral Sequin Prom Dress Poshmark Purple Sequin Prom Gown Long Size 6 Gem Long A Line Prom Dress with Sequin Flower Print Strappy Open Back Long Purple Prom Dress with Sequin Lace. Here's a beautiful long sequin prom dress that you'll want to pull from your closet again and again. Simply gorgeous for prom, galas, and other formal events, this corset back long formal dress features lovely.