How did gold panning separate gold from lighter material?

Panning is a mining technique that separates gold from soil or gravel by exploiting differences in specific gravity. Because gold has a high density, it sinks more rapidly than lighter siliceous materials when agitated in water.12

To perform this, a miner places gold-bearing material into a pan and immerses it in water. By applying a combination of shaking and gyratory motions, the miner allows the heavier particles to settle at the bottom while the lighter material is brought to the surface. The pan is periodically tilted to wash the lighter surface material over the side. This process is repeated until only heavy "black sands" and gold remain, at which point the gold can be recovered.12