this is a guide (not and encyclopedia) of rocks and minerals found in California.\n\n pros: laminated pages, categorized by rock/mineral type, informative, small and easy to carry in th3 field\n\ncons: not an exhaustive list of the local roxks/minerals, does not indicate what regions of the state each can be found in. \n\ni was hoping to give as a gift to a friend who is a newbie at rockhounding on coastal California. They found the information helpful, and yet still lacking. \nif you are looking for a reference sheet in the firld, this produt is perfectly adequate- however if you are looking for an exhaustive guide this might not be the one for you. - cheers!