Agates are found across the United States and in many other countries. They are in the chalcedony family of cryptocrystalline quartz. These beautiful rocks come in every colour, shape and size, and can be polished as stones or cut into thin strips for decorative purposes. Some agates are used in jewellery. Found in mountains, deserts and at seashores, agates are in all 50 states. Finding them is simply a matter of learning to recognise the stones in rough form, and then heading out for a beach walk or a hike across the land. Some places like old gravel beds, mining and quarry sites will let you dig on their grounds. Farms and fields may also yield agates when the land is turned with a tractor or tilled. Agate hunting can be highly rewarding for all ages, from novice to pro.
Purchase or borrow a book on agates from a bookstore or library. If you know collectors, maybe they will lend you books and pamphlets for identifying agates. The rough forms can look like ordinary rocks until you turn them over. Some are covered with nodules; you will begin to recognise them with practice. Knowing about the outer, lumpy, rough-rock appearance is quite helpful. Alternately, study images online, or go to a rock shop to look for rough samples.
Check with local rock shops, rock hunting groups and collectors to learn about local areas where you can find agates in natural settings, or places that allow you to hunt and dig.
Go early in the day or late in the evening to beach areas where sandstone cliffs may drop deposits of agates periodically. These get washed up onshore and range in size from tiny to a foot across. The larger ones are usually hardest to identify, but the small ones can be seen in the lower slope of sunlight. The angle of the sun lights the stones from behind so they stand out almost like glass.
Walk in the desert or volcanic-ash bed areas known for agate deposits. Make sure you take plenty of water. Look for the bumpy rocks with banded areas, or look for geodes and geode pieces. Chunks and pieces of coloured rock can also clue you in to favourable areas.
Dig in areas that either ask a fee or offer permitting for legal rock collecting. Some mineral crystal areas will yield a variety of agates, carnelian and jasper, too.
Hike in the mountains and foothills, or at lakefronts and riverbeds, keeping a keen eye out for the variety of specimens known to be in the area. Some rock shops will have guide maps indicating popular sites.
If you plan to be outdoors for any length of time, have plenty of water, sunscreen, a hat and sunglasses. Sunglasses are great for eye protection, but sometimes you will want to remove them to verify a distant rock that appears to be an agate. Take the rock identification book with you on hunting expeditions for quick reference.
Watch for snakes in certain rocky areas in snake country and out in the desert. You don't want to reach for a rock, pull it out and find a rattler under it. Walking sticks can come in handy for this purposes - use the stick to turn over any questionable larger rocks.