Best Natural Hotspring (in rocks or clay but not a man made pool)

by Karen
(Vancouver, BC)

Hi,
We are coming from Vancouver, BC on March 13 and have until March 17. I will be working for 14 days on a cruise ship as an RN. I would like to make the most of my time. We will be staying in Santiago, and will spend one day visiting the city. Then we have a car rented (hopefully that works ok, as reservations made, just waiting for confirmation) The car will be for 3 days, Mar 15 to 17 and we would like to go to some natural hotsprings. Not man made pool ones, but in rocks, sand or clay, etc. natural ones. We really like the outdoors and look forward to the Ande mountains. I have been looking and a lot of them seem like man made pools. Can you help us out?