The design of metal detectors well-suited for prospecting is an interesting process and not necessarily an easy one to achieve. It is a combination that blends the desires of what prospectors would like, the requirements of sales people and dealers, with the science and physics of what the electronics can achieve.

...these nuggets have not traveled far from the lode because the golden wire lattices would have been torn apart or flattened during weathering of rock and deposition by violent stream action.

When I teach people about finding gold, I often explain that it is helpful to think of any river or stream that carries gold as being something like a sluice box.