You can find jewelry almost anywhere on the beach. People take their rings and other jewelry off and lay it on beach towels and go play in the water, they come back and pick up their towels to pop the sand off from it then their jewelry is in the sand and gone before they realize what they have done.
The folks that play in the water lose their jewelry when their fingers shrink from playing in the cool water and throwing Frisbee's etc. If your hunting the sand your greatest results come from the high tide line to the low tide line and in the water to chest deep.
Is doesn't take long for coins and jewelry to get pretty deep on the beach, but the beach is ever changing and items are tossed around from the ever changing tides. An item lost today may be 10 inches or more deep tomorrow and 100 ft from where it was dropped, the next day it may be 3 inches deep depending on how the waves beat down the beach or sand it in.
The major key to finding good stuff is a machine that will penetrate deep enough to give a signal. There is a formula to successful beach hunting and reading the beach. You have to work the high concentrated areas where people play on the beach and in the water. The low areas where the beach sand has been pulled off from the surf will get you closer to the deep items. During the vacation season where there is tons of traffic I would concentrate on the wet sand and low tide line if you don't get in the water.
BCOOP