Some of these events can cause half of an entire mountain to plummet down into a gorge or canyon, damming up a stream system and causing a flood when the earthen dam finally breaks from the water backing up behind it.

Back at the entry point of the mine, we took turns slowly crawling down the slope leading into the mine portal with our metal detectors, hard hats and flashlights. The mine was hand dug and is about 75 yards long.

“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.”