I picked up this piece of wood when we were out walking over the weekend. It's not the first time I've found pieces that are the colour of copper when oxidation has turned it that beautiful verdigris colour. Each piece carries the hue throughout, but knowing this has never made me stop and wonder why. The colouration is caused by a pigment called xyleindein which is found in a lovely little fungus called Green Elfcup. I've never managed to find either it or the Scarlet Elfcup, but I live in hope. It's nice to have had one little mystery solved though.