Nokta FoRs Gold, a Gold Cube, 2 Keene Sluices and Lord only knows how many pans....not to mention a load of other gear my wife still doesn't know about!
I’m not sure what you see but I did notice that 2 of those circles are lined up in perfect straight line. 😏
All kidding aside, I’d guess gas bubbles trapped in the rock while it was forming then the rock eroded and exposed the pockets.