Florida gold is mostly natural, how ever I do wear a cob from the ATOCHA that Kip Fisher gave me.
Humphreys Gold Mine was located north of Regency Shopping Center, where the Southside Boulevard connector to State Highway 9A travels through. The dredging operation was not geared toward mining gold as the name suggests; it was merely a reference to the company name (Humphreys Gold Corporation, incorporated August 29, 1932 by A.E. Humphrey, I.B. Humphrey, and Judson S. Hubbard).
Starting in 1940, the area near Regency was mined for rutile, titanium, ilminite, and zirconium for the war effort; nearly a dozen precious metals including any gold particles were extracted when found in the area. The precious metals were mined for DuPont Corporation until the contract ended in 1957. The dredging operation excavated the top 50 feet of soil, performing a sifting and washing operation that would reveal and allow reclaiming of any precious metals. After 50 feet of earth was removed, the only thing remaining was the sand that had built up over millions of years.
In addition to the Regency area, the company had another dredging operation near Southside Boulevard in and around the Deer Park area. Per Mindat.org, the official location of the company in that area was on the west side of Southside Boulevard, 30o18'6" North, 81o33'48" West. A web search shows that Humphreys Gold Corporation also operated in Starke, Florida for a while as a subcontractor to DuPont. DuPont continues the operations at Starke today. The web search does not show very many other locations but the Humphreys Gold Corporation did have mining operations in other parts of the country as well, and in some gold was the primary metal being dredged for (such as in Montana).
After World War II, the Regency mining area operations continued and as a result it provided jobs for returning soldiers and others that were laid off as a result of the war ending. A large number of the people that worked there were from the Arlington area. The company closed local mining operations around 1957. The Denver based Humphreys Engineering Company was in operation up until at least 1966 and possibly longer.