St. Gillian Kay Unger purple vintage dress high neck

Vintage, circa 70s St. Gillian by Kay Unger purple dress. Near excellent condition, 1 small stain, looks like makeup on the left shoulder. Comes w/ removable belt. Elastic at the waist. Asymmetrical Button up w/ a slightly higher collar/ mock neck, Victorian like, very feminine! Some pintuck pleating at the neckline & shoulders. There is no fabric composition tag but I’m fairly confident it is a polyester material. I would describe it as a chiffon texture and I actually found a similar style vintage dress online by the same designer and that dress is listed as polyester -and the seller said it feels like a chiffon scarf. Size 4. Delicate, be gentle when putting it on. Between button 3 & 4 on chest may be a gape if you stretch, just how the dress is made but just be aware if you are on the bustier side.