Do you like rocks? Are you bothered if somebody doesn't call them minerals? Are you a fan of plants that you've grown yourself? Maybe of ones that you didn't grow?
Whatever the case, you should check out your Gathering skills. To access your Life Skills window, click on the "Life Skills" icon in the bottom-right of your screen. Gathering is highlighted by default.
There are four different Gathering skills in MapleStory 2:
Mining - Obtain common and rare ores from mineral veins.
Ranching - Collect animal products from your domesticated friends.
Foraging - Gather herbs from wild flowers and plants.
Farming - Harvest fruits and vegetables from your garden.
Be sure to keep an eye on the ranks of your Gathering skills. Higher ranks allow you to harvest higher level materials.
The amount that can be gathered is limited per category each day, so be sure to gather all that you can!