What You Need to Know Before You Buy a Rock Collection

Buyer Beware

collection of minerals and rocks in a box
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Boxed sets of rock specimens can be a good start for a child interested in geology. These rock collections are 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 some basic information, is all you need to begin. However, the most important part of a boxed set is your personal commitment to the child -- visiting lots of places together where rocks are found -- otherwise the whole experience is sterile.

What About a Rock Collection Box?

Skip the fancy, intimidating wooden box; cardboard or plastic 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, as it discourages close examination. A true geoscientist will pull the rocks off for hands-on learning.

    Other Items in the Rock Collection

    Many sets include streak plates and items to test hardness, like a glass scratch plate and a steel nail. Those are a plus. But the magnifiers that come with boxed collections are generally not trustworthy; they are the most expensive item and are the first place a dealer will cut costs. 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 of buying a rock collection is the pleasure of learning to recognize, pursue and cherish the rocks found in your own outings. 

    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. A specialized rock collection would have fewer specimens than a general one, of course.

      What About a Mineral Collection Instead?

      Rocks are more popular than minerals, and they're easier to learn about. But for the right child, especially in a locality with notable mineral occurrences, a boxed mineral collection may be just the thing to start with. And for most budding rockhounds, a mineral collection is the ideal second step after getting a rock collection. Becoming a real expert in rocks requires strong skills in mineral identification. Another aspect of mineral collecting is the possibility of visiting rock shops, near home as well as on the road, to buy more specimens inexpensively.

        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 a rock collection 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.