Rock hammers are fun to use, and they make geologizing so much easier. But there's good practice and bad practice when it comes to using a rock hammer. I'm writing up the subject this week, and safety seems like the first and most important thing to address. Moreover, I think that safe use promotes conscientious use. So I've laid out the basics of safe hammer use.
You should definitely master safe use before you even think about more advanced hammer techniques, like using them for opening beer cans or killing rabid bobcats.
Sandstone and the hammer that cracked it Geology Guide photo