Since the 1849 Gold Rush thousands upon thousands of holes, pits, trenches, shafts and tunnels have been dug in search of GOLD. Most of these diggings have shown only a trace of gold, if that. My advice is don't give up, as through the years other very valuable metals and elements have been discovered in these so-called worthless diggings. That is not counting the big five; silver, lead, zinc, copper and gold.
Tungsten, uranium, bismuth, tellurium, cadmium, nickel, platinum, mercury, iron, molybdenum and many others have dozens of uses.
However, one might focus on the following element that could make you a millionaire literally overnight.
LITHIUM along with cobalt and manganese are used in batteries that will power the cars of the future. Lithium is found in dry lake beds, pegmatites and in certain clays.
RARE EARTH ELEMENTS (REE) These elements (17 in the group) are found in many different environments usually associated with thorium which is radioactive. Some of the REE elements are used in cell phones, TV's, computers, etc.
The average prospector will probably walk over the above mentioned elements looking for a few specks of gold and miss a fortune. My suggestion is if in doubt run a test at a reputable lab. Even after my 45 years+ of prospecting I have a difficult time identifying many of the above elements; however, I have found all of them in small quantities through the years. During the past year I have started to focus on these rare earth elements looking for a large commercial deposit.
Good luck and STRIKE IT RICH.