I'm going to do what Michael Welland did in the comments over at Callan's NOVA Geoblog and list just a few things That Every Geology Major Should Know, rather than try for 10 that no one else has listed. Here are my top four, which are all required to get work in basic mineral exploration:
1. Know how to identify some rocks accurately (notice I didn't say all rocks).
2. Know how to identify some minerals, including some obscure ones, accurately (notice I didn't say all minerals).
3. If you can't identify a rock or mineral, then know how to describe the rock or mineral in question, preferably in well-written sentences when sentences are necessary.
[These are the three main things, four counting writing about rocks and minerals, that I taught to upper-class geology majors when I was in grad school. The writing part was the hardest to teach - many students thought it unimportant.]
4. And I'd really prefer for all geology majors to understand that all the things we use are either grown from or on the earth (plants and animals) - or they come directly from the earth itself, from minerals, elements, and related earth products or chemicals.
Presumably all geology major or graduates know these things.