Metal detecting enthusiast here!

How does changing frequency help to better determine gold? I continue to read that a metal detector of the same manufacturer operates at 18 kHz to better detect gold. Another manufacturer is going to release a new coil, which operates at frequencies of 15 kHz, 30 kHz, and 55 kHz, which will detect gold even more efficiently. Why does increasing the frequency help locate gold with a metal detector?
Can anyone explain this?

not a clue mate, lets hope someone has an idea as it would be interesting to hear

To cut a really really really long story short.

All EMF frequencies will detect gold and just about every other metal.
      Low frequencies 2khz to around 19khz khz will respond well to gold of around 1 gram to monster size from the surface to significant depth of approx 2+ feet in quiet to moderately iron mineralised ground. when used with  4 to 14 inch coils.
      Higher frequencies will detect/respond to very small gold 1 grain to 1 gram within a few inches of the surface but lack penetrating ability in high iron mineralised ground and become difficult to ground  balance.
       Lot of other stuff comes in to play but this is the absolute basic results possible with very low and  higher frequencies.
Low frequencies for large deep gold and high frequencies for small shallow gold.
As yet the frequency cannot be used to ID gold.

G'day thomasquarry, welcome to the forum.

Although gold size in itself, affects detection depth in general, as Adrian stated, higher frequencies or that of higher pulsating rates (as that on a pulse induction detector), will respond better to finer smaller gold, such that of fine gold in specimen host rock, or on that of fine/thin sponge/leaf gold, including that of tiny solid alluvial gold, whereas that of lower frequencies (KHz or pulsating rates), have the opposite effects, by punching deeper on the more denser, heavier, smoother rounded, alluvial gold types.
The hunt to chase all/any in ground gold type, by the use of just one single frequency or pulse rate alone, as best suited on all types of gold, has been going on by all metal detector manufacturers, from when the earliest of metal detectors designed for the prospecting of gold were created, but to little or no avail. This is because there is no one single frequency/timing, that can perform well on all or any gold type/size, or on any other positive in ground target for that matter. This is also why metal detector manufacturers today & or over the years, have introduced or have incorporated, more than one detectable frequency, or variable/multiple frequencies/pulse rates on their detectors, in order to cover the numerous in ground variables, associated with the detection of different type/size, in ground metals in general.

Cheers Kon.

X Ray and infrared spectrographic analysers can ID gold and many other minerals but these gadgets do not lend themselves well to hand held hobby type metal detection. XRF mineral analysers are nifty instruments that cost thousands of dollars 30,000 or so but you cannot stroll around the bush waving these items over the ground like a conventional metal detector searching for nuggets. They can of course be used for detecting fine gold in various rocks and qtz reefs. A bit of training is necessary to be able to use these instruments correctly. They do after all transmit X Ray radiation.

I would prefer to go hunting for gold, but the only really interesting places remained - Alaska and Australia, and I would prefer to stay in the UK. I am still working on my map. Having said that, I did a little in October last year in North Carolina (where gold was first found in the United States) at the John Reed gold mine and in the city of Termal. https://en.wikipedia.org/wiki/Reed_Gold_Mine