Rock hunting and gem collecting can be part of the hobbyist's life or that of serious lapidarists and jewelers. While it's quite simple to find gems and minerals (in raw or polished forms) at rock shops or gemstores, finding them in nature can be pleasantly rewarding. Learning to identify the many types of stones you may come across is key to determining whether or not something is a "keeper." Sometimes, just being outdoors in promising environments while searching for gems will reveal aspects of your world you may not have known before. Enjoy the journey as well as all the stones that will weigh down your pockets or packs.
Purchase a book on gems and minerals that has photographs of various stones, especially the ones you are looking for. Ideally, these are shown in their raw state. Learning to identify crystals from their matrix, or by knowing what to look for in the outer stone helps you become more adept at quickly culling through a rock pile.
Visit a rock or gemstone shop to view samples of stones, too. Large rock and mineral shops will often have large containers of what appear to be ordinary rocks, but upon closer inspection reveal the depths and qualities of gems awaiting cutting and polishing. These containers are usually well marked with identifying rock names.
Walk a beach beneath a sandstone cliff if you live near one, or do so when traveling. These can be sites where agates and carnelian slough off hillsides, fall into the sea and get tumbled naturally. Then they show up on shore. The best time to look for such rocks is in the early morning or late evening, when the sun's slope is low. The rocks get backlit and are easy to spot. Keep an eye out on other beaches, too, as these stones often get taken downshore by weather systems and currents.
Get out your local rock finding map. You can get these through rockhound organizations, online or at some bookshops. Pore over the map and identify places to hunt in your area. Rivers, lakes, ponds, streams and rocky hillsides may reveal amethyst geodes, quartz, jasper and many other stones.
Gather any necessary equipment and go to those areas. Make sure you have proper permits or permission to dig in the designated sites, and never dig on privately owned land unless you have pre-investigated the right way to do so. Digging for rocks on national park lands and similar areas is not usually permitted. But you may find stones in some places -- check with the local authorities regarding whether or not you are allowed to keep such discoveries.
Go to a rock mine. These can also be mines known more for ores (which are also rocks) but some will welcome the general public and allow people to dig. Often a fee is asked of visitors to such places, but you usually get to keep everything you find. Some places provide all the tools and safety devices, but not all do, so check in advance by contacting the company's managers. Some mines specialize in one particular type of rock or mineral, but in certain areas you will also find many forms of quartz, malachite, various feldpspars and calcite. Follow the rules at each location.