Hi,From New Zealand [KiwiLand]
Looking at your picture, a story come back to my mind :
When I was in New Zeland in 1977, I saw on the TV news a guy who loaded on his truck a rock about three time bigger than this one from the sea side.
Nobody cared until it was found it was a block of opale.... you should go back to the place may be ....:ROTFL::ROTFL::ROTFL:
Michel