Every rock store has a good rock hammer. There are features to like about each. Small light ones for chipping specimens out of host rock with accurate blows. They will normally be smaller then a regular framing hammer with a pick end and an opposing mallet end for smashing rock. Type rock hammer into your browser.
Eastwing hammers have lifetime guarantees, so if you ruin it even by misuse you can take it anywhere they sell them and get a new one. One end is spiked the other flat.