Originally Posted by feline fanatic

Hmmm, that looks more like bleed from another fabric to me. Seems to me if the metallic was reacting in some way it would be all over the block, not blotched like it looks and even into the block right next to it the one with the flowers on a wavy line. I would put this quilt in a non water efficient washer, like a top loader high capacity one at the laundermat and a bit of blue dawn dish soap and give it a good soaking to see if that green comes out. You can also do this in your bathtub.