White carnival glass swan boat shaped dish, 60s - 80s vintage, not an antique. Beautiful color here, iridescent luster on clear glass.
This looks as though it does have a makers mark which I could barely see, even with the camera. I've been told it's an Imperial glass piece.
It measures about 9 1/4" long end to end x 5 3/4" tall, a nice large piece to hold flowers or greenery or an impressive display on its own.