The ACE 250 should find Gold Rings and some gold jewelry. It's not a prospecting detector.
I suggest that you find some examples of what you might like to find and test your detector with them (ie. put the samples in plastic bags - 1 item per bag) - place them on the ground and see how well they are detected. I prefer this sort of test to 'air' tests - which usually don't reflect real world detector operation all that well.
Amazingly enough, the Tesoro Compadre (the least expensive Tesoro) is quite good at finding fine gold chain. It runs at 12 Khz - that helps a lot.
The ACE 250 operates at under 7Khz, that makes it less sensitive to small gold in any form,