One of the best rockhounding books I can recommend is "Arizona
Roadside Geology" by Halka Chronic. We have a well used copy in the
truck for our all-too-rare-lately road trips.
There's also an Arizona Gem Trails available, though I don't know
who the author or publisher are.
Depending on the locality, you can find anything from quartz
crystals, zebra jasper, azurite, dolomite, fossils such as
trilobites and horn corals, chert, sandstone, limestone, basalt,
rhyolite, amethyst (some of the best amethyst known comes from the
Four Peaks mine in AZ).
I believe there is also a "New Mexico Roadside Geology" book but I'm
not sure if it's by Chronic. VERY generally speaking, the geology of
NM and AZ are very similar. If you e-mail me off list, I'll get my
copy of Chronic's book out of the truck and I'll give you more
If you get near the Phoenix area, give us a call or come by and see
Deb (dredging this up from my "seems like a long time ago"
avocational paleontology in AZ memories)
AZ Bead Depot
Apache Junction, AZ