Any professional prospector will tell you that proper classification of placer material is the most important single step that leads to high Recovery of placer gold. You will be amazed how easy it is to recover micro-fine gold, if it has been classified to the approximate size of the gold. Always process the contents of each pot separately. Gold will separate much faster when the lighter materials are less than five times its mass. Specific gravity differences between gold & sand are what makes gold panning machines effective. When grains of gold, black sand & brown sand are compared, it will be noted that if the weights of the grains are equal, the size is greatly different. Likewise, if the grains are classified so that they are uniform in size, then the weights are very different. it is this size to weight ratio that makes classification important when using a panning Machine or when you are panning by hand.