Good morning all, I have come across something I have never seen before and thought it would be a good idea to see what my panel of experts have to say. I have some assemblies that are showing a purple stain in the laminate around the gold contacts of a board edge connector. Under the microscope, I see no sign of anything on the laminate on the boards from stock. I took a sample of the stock boards and ran them, unpopulated, through the reflow oven and - lo and behold - I've got a stain. The stain seems to be in the epoxy. A little light scratching with a knife blade takes off something purple. Any ideas as to what I am looking at? Gary Camac