Sean, size matters in this question. The meter/screen is only measuring conductivity, as you know (not "composition"). And size plays into conductivity.
For example: take an entire aluminum can and wave it in front of your Explorer. Make note of where it reads. Probably way up around quarter in the upper right of the screen, right? Now take a little fingernail size snippet out of the
same can (or the tab portion, or a beaver tail off the old style tabs, or whatever), and wave that in an air test. Where does
that read? Down low, right? But wait!! They're both the exact same compound: Aluminum, right?

What changed? The size! So too is the same principle for gold. I guarantee you that if there's a $20 gold piece on your property (or a gold bar or whatever other big sized thing), it will read in the upper right of your Exp. screen

But a dainty little earing, or tinsel thin ring, or $1 gold piece is going to read very low, around foil, tab, or whatever, right? So you see, there is no one "sound" or "coordinate" for gold.
And unfortunately, gold and aluminum share the same conductive range. And each has oodles of variations of sizes, shapes, wad densities, etc...
And the karot of the gold plays into it: The alloys that gold is mixed with (to make it 10k, 14k, 18k, etc...) affect where it hits on the conductive scale. Pure gold (24k) is actually a very high conductor. So a 24k ring, even though small, will read high up around penny. But the same exact sized ring that is only 14k, would be a mid or low range on the screen, d/t the alloys.
If they ever make a detector that reads composition, rather than conductivity, is the day we'll all get rich digging gold rings till our arms fall off! Until then, if anyone tries to tell you gold reads at a certain coordinate, or sounds a certain way, then do this: take that person out to the nearest blighted inner city ghetto park, and turn them loose. See how much gold they dig up, while leaving foil and tabs behind
