Tourmaline prices can be all over the spectrum and it really depends on the color, quality, size and often from where it came from. See the link below to sold Auctions on eBay for Tourmaline specimens. As far as the Nugget is concerned, I would advise taking it to a professional Jeweler, a Gold/Silver/Platinum Buyer or even a Pawn Shop to have it tested. They should be able to tell you if if is Platinum or Silver fairly quickly.
Sorry, I don't have pics of my' Gem finds and it would take some time to gather them together for me to take pics as they are scattered all over the house and two garages!
Frank