Make sure to check out Jewels by Joseph in Newport Beach. They are a family owned business & family friends of mine. Jim Hartstein is the owner & his daughter Claire works there as well. Jim's sister, Barbara, also works there & the entire staff is extremely helpful. Good luck!
Jewels by Joseph
948 Avocado Ave
Newport Beach, Ca. 92660
Ph#: (949) 640-6788
Fax# :(949) 640-6785
Jewelry by Angelo in Laguna Niguel by the new whole foods. Family run, awesome people, all work done in house.
I always take my jewelry for repair to Jostmar inside South Coast plaza. The prices have always been reasonable and they do a pretty good job.
I had a great experience at South Coast Jewelers - they have an appraiser on site (which is why I sought them out) - and I also had them repair a bent prong on my engagement ring. Work was fast (done in an hour), high quality, and reasonably priced. They are on Bristol just outside of South Coast Plaza.
You can also try Jared's the Galleria of Jewlery in Mission Viejo.