"HorseIsle" is a virtual, horse-themed online game. There is no real gold or gold nuggets to be found in it, as it exists entirely in a digital world.
Perhaps you're thinking of a different game?
If you're interested in finding gold nuggets in the real world, keep in mind that gold panning and prospecting require specialized equipment and knowledge. It's best to research thoroughly and consult local experts before attempting to prospect in the wild.