For anyone that wishes to learn, below you will find a free opensource/interactive geology based textbook I used for my intro to geology class in college.
Pretty neat and useful information. Albeit, it gets into geologic hazards and what not, but there is still a lot of useful information about learning rock formation and mineral identification which can give clues to where the gold can be found!
Here is the link:
http://opengeology.org/textbook/