Hardscrabble---
I don't know whether or not signs of gold underground can be detected with a camera, but I think it's not impossible that it could.
I have seen several sources over the years, stating that there are
many reports of the phenomenon occurring, where it can even been seen with the naked eye, with precious metals having then been found at the location. That, of course, is not proof.
Gold does seem like a very stable element, since it doesn't tarnish or rust. But there are several chemicals which will dissolve it completely. Cyanide, iodine, thiosulfate, chlorine gas, and the popular aqua regia acid mixture, are among them. Many households, especially if there is a swimming pool, already contain chemicals which, when properly combined, will dissolve gold very nicely!
There is a current theory that all gold deposits are formed when super heated steam drives it way up through the earth, carrying dissolved gold, and other precious metals, plus other stuff. Gold ores are often a hardened "soup" of many different materials (some of which are very toxic). And sometimes it precipitates in mass, forming gold wires, crystals, or large pieces, of fairly high purity, within various types of host rock.
So, for ore anyway, who knows
what possible combinations of materials commonly associated with gold deposits might off-gas something which could be seen above the surface somehow?
Refined gold, such as coins and bullion, might be considered less likely to produce anything detectable, but when buried underground, who knows?
Gold being very conductive might have something additional to do with it, too.
My opinion is that ultimately, things are what they are, and if it happens, it happens.
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