In my opinion target separation is always more important than target depth when it comes to searching for jewelry at popular beaches.

The opposite applies to searching for old coins and artifacts at less trashy beach sites known for shipwrecks or beaches with a little history. 

It still surprises me just how much value is put into target depth at popular beaches by people searching for jewelry with a metal detector.

From experience I can tell you the hardest jewelry to detect is often the shallowest jewelry as if it is hidden in plain sight.

No doubt a lot of gold I have had the good fortune to recover at beaches was simply missed and left behind by speedy beach hunters or people swinging their metal detectors like golf clubs.

Perhaps some gold was also left behind by beach hunters who simply got bogged down digging deeper clad coins and junk instead of eventually running across the gold I detected.

I use search coils designed for target separation when I search beaches known to draw large crowds and I use my ears as my main discrimination tool.
I also never worry about what I am potentially missing by hunting in the all metals mode or sweeping an extra large pizza box size search coil, I concentrate on detecting shallow or partially masked gold.
A lack of metal detecting finds always has more to do with site selection, equipment choice and search techniques than beach or water hunting conditions. 
For example, I often use small sniper size search coils in very trashy areas of the beach to spice things up.
If you sweep an 8-inch search coil at a trashy beach entrance you will find gold a 10-inch search coil will simply not be able to detect. It makes more jewelry hunting sense to try to detect and recover shallow gold than deep golden  trashy areas of the beach.

Look at using a small size search coil as driving with low beam headlights in the fog, reading less is actually more beneficial in the long run.
Think about it, if you search heavily hunted beaches why on earth would you be concerned about deep targets? 

Skimmers take coins and the odd piece of jewelry at heavily hunted beach sites, but they cannot get it all. 

Fresh dropped shallow gold is often hidden when it is laying next to a bottle cap, clad coin or other undesirable object, you have to give yourself a chance to detect that gold on the first or second sweep across where the gold has come to rest. 

Two sweeps and step forward or as I like to refer to it, rinse and repeat beach gold prospecting. 

I believe there is always something to find if you find a way to find it, you just have to put your search coil over it in trashy areas of the beach.

You can winkle gold out of the most trashiest of areas if you learn how to sweep slow and low using a small search coil. 

Note to speedy local beach hunters, I am that guy you see as you walk onto the beach and the guy you see in the same place you returned to after you took your long walk. 

I can tell you from experience gold likes to hide right next to objects that help mask it from detection. 

For tips on how to find gold jewelry at the beach, check out my beach treasure hunting guides at www.garydrayton.com