It all occurred when Gus and I returned to a remote placer gold area where we had previously found really good gold. The problem was that it would take about an hour to walk through the desert to get to it.

“Much of the ground where Ms. Hollingshead found her diamond is made of unweathered volcanic rock. When it rains, flowing runoff often leaves loose gravel, and sometimes diamonds, on the surface in these areas.”

You might think that gold prospecting techniques are basically the same everywhere, and in many instances you’d be correct. Some geographical locations, however, due to their unique geological conditions, present unusual challenges...