Mineralogy is the only one you can leave low. The terminology is a little misleading, but you'll need all the other skills. On the skills pane of the crafting equipment / skills / attributes, the top two listings relate to refining skills and the bottom two relate to finishing skills, regardless which speciality you end up choosing. In the Mineralogy / Carpentry / Artificing group, you'll want to leave one 0 or low if you intend to specialise, which most do - in your case, you'd ignore Mineralogy and let the other two max out.
Balancing them, however, seems to be less useful for most than trying to keep one or two relatively high and leaving one to lag behind somewhat. Bear in mind that you will never have enough points to max out all 3 skills in a group. I tend to let utilities max out because it's what's used to maximise quality (and because it's used so much it tends to go up more/faster than the others anyway). After that I try to get station skills (the one not utilities or tools) get pretty high, because aside from helping on station actions, it also helps reduce the incidence of complications... though I'm not convinced it's working all that well lately. ;-) I leave tools the lowest in both finishing and refining partly because it's hard to raise, and I figure I can plug the gap with gear that will enhance related attributes and the abilities themselves.
That, however, is just how I like to do it. I'm sure others will chime in with their own strategies.
