Ivconic's Negative Ion Detector circuit

[Carl-NC]

Originally Posted by J_Player

As far as a special field around buried gold, there is a lot of evidence from conventional detectorists to support this. Many detectorists talk about a "halo" around old coins and gold they find. They say they get a really strong signal on their metal detector, as if the coin is much bigger than what they actually dig up. But after digging up the coin, it then gives a normal signal, even if they bury it again.

These are anecdotal stories, and have not been backed up either in experiments or in theory. Oxidized iron can definitely produce a larger response under certain conditions, but copper or silver oxides probably do not. I've read on other forums where a couple of people have tried to experimentally verify halos, and have failed. I suspect halos are mostly a myth.

The explanation I heard is these coins develop oxides and other salts around them after they are in the ground for a long time. Apparently it takes a lot longer for gold because it more inert than silver, copper and other metals used in coins and jewelry. But even gold does form a very thin film of oxides and other salts after it has been in the ground long enough (most gold has a certain amount of copper or silver alloyed that will also corrode slightly at the surface and leach into the soil over time).

Gold does not produce oxides, at all. Metals (copper, silver, etc) alloyed with gold will corrode, but not the gold.

- Carl