Well, Argentium, it was on the bottom of a steep 10' cliff of exposed rock and soil. I recon it likely worked its way loose from the hillside over time. Needless to say, in Gold Country. But also, an area familiar with fires. Without giving the spot away completely, there are old mines nearby and nuggets are sometimes found by treasure hunters and casual observers.
Recently, I had in my possession, a nice 26.5 gram nugget. Though it looked much different, being a river find, the weight differential seems to be proportionally similar. But I'm no expert.
I'd be overwhelmed if it turns out to be Gold. But just the same, if it's not, it's a wonderful roller-coaster ride. :-)