aa battery,
Lots of places to detect around the Quartzsite area, but the east side of the Colorado river from about I-10 to Parker is not one of them.
Almost all of that is on the Indian Res., don't get caught on there with your detector.
Its not near all hard rock country. Lots and lots of placer ground around the area.
To name a few: Trigo placers [mostly on the Military Res.]--La Paz area--La Cholla area--Oro Fino placer area--Plomosa placers--Middle Camp placers and many other small areas with no names, if you know where to go.
Remember a lot of these are tied up tighter than Dicks hat band ie. [under claim] and some of these guys can get a bit on the grumpy side if they catch you on their claim detecting.
The KOFA area south of town has a couple of large hardrock as well as placer mines and whats left of the old town, but that area is off limits as its on the game range. Nice area to drive through and visit. Very rough.
Maby this will help a bit.
Bob T.