Help date this dress please!

Hey everyone,
So I have this gorgeous dress that I picked up at an estate sale. It is in amazing condition. It is what I am calling a kimono dress. There are no tags but has a metal zipper up the back. I believe it is polyester though it seems light for that. The sleeves are attached to the dress. It really is gorgeous! When I googled it I came up empty with no images matching the design. Anyway, I'm not sure of the time period to place it in. I think it is 1960s? I've never come across this type of piece before so really information would be great! Thank you in advance,
Lauren

 

P.S.
Found out it's called a caftan from Hawaii! Sometimes you have to ask Grandma! Now we are cooking with oil!

 

I would think late 60s.