Originally posted by PenPusher The blue Lagoon in Iceland has a very similar colour, I wonder if it has something to do with volcanic origin ?
The New Zealand South Island Fiordland hasn't seen much volcanic activity for a long time as far as I can tell. I wondered if there was a chemical like copper sulphate in the water. The only explanation I've seen claimed that it was refraction, but if that was so, you'd expect every clear stream to be the same colour, and that's not the case. Unfortunately, I haven't been able to find an explanation. However, your suggestion may have merit because I've seen very blue pools in thermal areas around Rotorua in the north island, plus of course the prismatic spring in Yellowstone.