If you're not familiar with the area or with field collecting, start with a local museum. The San Diego Natural History Museum, the San Bernardino County Museum , and the Fallbrook Gem and Mineral Society Museum offer programs in geology for all age levels. They'll also help you find out what kind of permission you need. Collecting anywhere without prior permission is illegal, whether it's public or private land. There are very few mines available for open collecting in San Diego County.
Many mines are extremely dangerous, especially if they have been closed for a while.
Please stay away from them. If you are interested in learning about the history of mining in the northern part of San Diego County, or in a guided trip to a mine, please contact the Fallbrook Gem and Mineral Society Museum . Contact the San Diego Mineral and Gem Society . They have several sections and lots of opportunities for you to learn how to tumble, polish and shape stones safely. The Gemological Institute of America has moved its headquarters to San Diego County, near Carlsbad.