This patch is from David Lynch's Dune. It displays the colors of House Atreides, and the gray background indicates that it would have been used on the uniforms worn while still on Caladan.
It looks like the type of patch used on the Atreides soldiers' hats, I'm 99% sure it's unused -- it doesn't look like it was ever sewn to anything, and a friend of mine who does costuming for Broadway shows agreed. I guess it was a spare. Maybe I'm wrong, though. If anyone knows more about mid-Eighties film costuming, I'd love to hear your thoughts!
