I found this striking lichen on Mt. Tamalpais in Marin last weekend.
It was even more emerald in color in situ. The rock was just shy of the big serpentine outcrops that you get up at the top of Mt. Tam. I was interested to see if any lichens could stomach the asbestos-laden California state rock. Not many could. But here's one piece of serpentine that seemed to be able to host lichens. Maybe it was at the edge of the outcrop and so less pure.
