Lightning Ridge Black Opal: This amazing Opal it is like lightning bolts that flash and change as it moves. Lightning Ridge mine site in New South Wales, Australia. Lightning Ridge black opals are the most valuable in the world. Lightning Ridge is one of the few places in the world where the precious and highly prized black opal is found. Unlike other opal, the black opal contains carbon and iron oxide trace elements, producing a very dark stone which has hints of blue, green and red play of colour.