Trouble was, the gold was surrounded by "blue stuff" that clogged up their rockers, primitive devices miners filled with water and gravel and swayed back and forth to sift for gold.

But someone sent a sample to an assay office. Three weeks later, the report came back.

The "blue stuff" was silver, valued at nearly $4,000 a ton.

Soon the rush was on to Ophir, as the tent and shack community of prospectors quickly became known.