The Gold Bug Pro and G2 were designed principally as gold nugget hunting detectors (All Metal mode) with the added benefit of having a general application search function (Discriminate mode), and sine gold jewelry generally falls in the smaller-size and fits the lower-conductive range, the Gold Bug Pro/G2 detectors can do rather well, but .....
There will be some trade-offs based upon the search mode, the settings, and the operator's ability to master the performance characteristics of the Gold Bug Pro and/or G2 models. Also, the search coil choice has to be considered in the application of these detectors at jewelry-potential sites. Best depth and sensitivity to lower-conductive targets will be achieved in the threshold-based All Metal mode, but few coin and jewelry hunting hobbyists will use this method. Most are going to search in the motion-based Discriminate mode so let's consider this approach.
Using the Discriminate mode I would suggest not rejecting anything above a VDI number of '40.'
I would also remind users that the very quick auto-tune speed of the Gold Bug Pro and G2 models will require the operator to find the best faster sweep speed possible to use w/o being too fast for the mineral ground make-up. A too-slow sweep speed will reduce the detection depth potential due to the very fast response and recovery rate.
Survey the site you select that might hold gold jewelry and be sure the best coil you have is put to work. Since October of 2010 my best gold jewelry recoveries using my G2 have come with the 5" DD coil mounted. One reason is that I use it the most on that model, but I'd opt for the 5X10 over the 7+x11+ DD coil in more open areas as I have had better responses with that coil.
Now, operating frequencies set aside, I will say that I have had better gold jewelry success using the 6.59 kHz Classic ID and IDX Pro, the 7.8 kHz Omega and