Boxed sets of rock specimens can be a good start for a child interested in geology. They're handy, small, and not too expensive. Books, maps, a good rock hammer, a magnifier, and the guidance of local experts will take your child much further. But a modest rock set, especially one that includes a pamphlet and a few basic tools, is all you need to begin—that plus visiting lots of places where rocks are found.
What About a Box?
Skip the fancy, intimidating wooden box; cardboard is sturdy enough. You can always buy a better box later, and more of them to fit a growing collection. Don't buy collections that are glued to a card—that discourages close examination, and a true geoscientist will pull the rocks off for hands-on learning.
Other Items in the Box
Many sets include streak plates and hardness-testing items like a glass scratch plate and a steel nail. Those are a plus. But the magnifiers that come with boxed collections are worthless. Children should have a decent 5x magnifier or loupe, purchased separately, that rewards them with a high-quality visual experience. If a pamphlet comes with the set, review it yourself in case the child needs help with it.
Start Small
You can get huge collections, but a box with about 20 specimens covers the most common rock types, with maybe a few extras for color or exotic interest. Remember, the point is the pleasure of learning to recognize, pursue and cherish the rocks found in your own outings. There is none of that in buying a big collection readymade. And if the child loses interest, little is lost.
Get Rocks, Not Chips
A useful rock specimen is at least 1.5 inches or 4 centimeters in all dimensions. A proper hand specimen is twice that size. Such rocks are big enough to scratch, chip and otherwise investigate without spoiling their appearance. Remember, these are for learning, not admiring.
Igneous, Sedimentary or Metamorphic?
There's merit in getting a set of rocks that reflect your own region—but a set of exotic rock types might fascinate someone who travels or dreams of traveling. Are your local rocks igneous, sedimentary or metamorphic? If you don't know, it's easy to learn yourself—really. Use my simple identification table to identify your rocks.
What About a Mineral Collection Instead?
In my experience, rocks are more popular than minerals, and they're easier to learn. But for the right child, especially in a locality with notable mineral occurrences, a boxed mineral collection may be just the thing. And while a second box of rocks is probably wasted money, a mineral collection is the next logical step for a budding rockhound. Becoming a rock expert requires strong skills in mineral identification.
Reading Matters
A rockhound of any stripe, whether a collector, a prospector or a full-fledged geoscientist, must be able to read texts and maps as well as rocks. If you're buying for a child, for best results be sure he or she is comfortable with print and has a basic grasp of maps. Without reading skills, a child will always be limited to gazing and dreaming. Scientists need to gaze and dream too, but they also must read, observe, think, and write. A rock kit is only a start.
