How to find gold (and other heavy minerals).
Everyone who have ever to a beach have probably seen this kind of red or dark layering in the sand.
What few know is that these kind of dark mineral deposits are the perfect place to look for heavy minerals.
The reason being that some kind of fluviual process (in this case, wave action) have removed all the lighter minerals like quartz and feldspats, and therefore concentrated the heavier stuff in a handy lens or layer.
Some of the heavy stuff left behind may for example be grains of gold.
Its like nature have been panning vast amounts of sand for you