This is a mid to late 1960's Ben Zuckerman coat in a rich royal blue velvet. The coat is double breasted and has a half belt in the back. There are large patch pockets at the hip and the buttons are really fantastic- blue rhinestones surrounded by clear rhinestones.
Velvet was a very popular fabric in the 1950's and 60's, mostly worn for evening events.
Photos courtesy of  Magenta1031.