Fabulous dress form the 1960s substantial construction, strong thick jacquard damask fabric that glistens and shimmers, and is a natural based satin; not synthetic: likely rayon/viscose or silk content. Lined throughout, and tailored beautifully if your size (sadly too big for me)  No makers label so possibly seamstress made, but finished with a small bow at the back zip top. The neckline is a ruched boat-bandera line, and the hem has a similar effect.
Immediately makes me think mermaid this dress though it is slight A line not flared from knee as we normally reserve that term for. In fact Marina the mute mermaid that stole Troy Tempest's heart from 1960s tv show Stingray wore a slight A line maxi though hers was a floaty fabric. This most definitely isn't floaty; the shape is all and a bent knee in the dress can cut a formidable aesthetic as the light shimmers off the fabric....and that psychedelia wave swirl pattern is fab. Ideal for the New Psych or Mod aficionado. Worn with hair up with a coiled back bun attachment would look period & lovely too showing off the neckline. Too big for me sadly - I'm a size 6-8 so had to pin it but it is tailored.
Really is spectacular in the sunlight and would highly recommend this dress for a UK size 10 for an evening summer event particularly a sixties night on a cruise or the yacht club terrace for cocktails. Such a dress would of course have been worn with long gloves at the time: but avoid modern cheap satin imitations: these are awful! I have also teamed it with a large shell necklace for a sophisticat does '60s beatnik look; necklace not included! 
This dress because of it's substantial construction would be great for even glamping or a houseboat evening...and you really will shimmer like a mermaid. But sadly can't tell you who made such a beautiful piece....it's rather a mystery. But sometimes...it's nice to have that unique element....perhaps it was fashioned by some underwater siren using luminescent threads from the deep! It's quality, for sure.
 
"Marina... Aqua Marina,
What are these strange enchantments that start whenever you're near?
Your magic to me, a beautiful mystery.
I'm certain to fall I know, because you enthrall me so...."
 
As the Gary Miller 1964 end theme from Stingray went....
This is a dress for the girl who embraces 'anything can happen in the next half hour' confidence....