Rock Hounding

Family Home Evening Resource Book, (1997), 308–9


Rocks can be fascinating to young and old. A simple collecting trip requires little more than the desire to get outdoors and to notice the geological wonders of the earth. Collecting rocks, or just looking at interesting ones, can be a fun family activity.

Materials Needed

  1. 1.

    Cold chisel for breaking off a sample

  2. 2.

    Magnifying glass for examining what you collect

  3. 3.

    Knapsack or heavy canvas bag for carrying samples home

  4. 4.

    Pocket knife for cleaning

  5. 5.

    Newspapers to wrap fragile specimens

  6. 6.

    Old gloves to protect your hands

  7. 7.

    Mineralogist’s hammer (blunt on one end, pointed on the other) for breaking off samples

Activity

Prepare for your rock hounding trip by first choosing an area that has interesting rocks. You may need to check with local experts at a rock shop, university, or gem club for advice on where to collect. The best areas are where rock is exposed—a quarry, mine dump, excavation gravel pit, stream, beach, road cut, dry wash, or plowed field. The best time for finding good material is often in the spring or after a storm, when fresh rock is exposed.

Be careful to obey the laws of your country. In the United States, rockhounding is usually legal on public lands, but not in national parks, national monuments, and other restricted areas. It is also against the federal law to collect vertebrate fossils and Indian artifacts in the United States. Collecting on private lands requires the permission of the owner. Obeying the laws of your country, using courtesy, and taking good safety precautions can help to make your trip more enjoyable.

Once you have chosen a place to hunt, plan your trip. You may want to take a whole day with the family to collect rocks, eat lunch, and enjoy the outdoors.

Use moderation in gathering your rock samples. Take only the most interesting ones. It’s a good idea to devise a labeling system so you can keep track of your collection in the field and at home. A simple system is to label each rock as you find it with a number on a small piece of adhesive tape. Record the number in a notebook with a description of the rock, the place you found it, the collector, and the date.

There are many things to notice in the rocks you collect, including hardness, crystal form, color, cleavage, fracture, possible magnetism, and luster. You might find it interesting to test the hardness of the stones you find. Knowing the hardness of rocks can help you identify them.

The Mohs scale, developed by Friedrich Mohs, is the hardness scale used by mineralogists. On this scale, 1 is the softest and 10 the hardest.

The minerals named in the scale are the ones that are typical for that hardness.

  1. 1.

    Talc

  2. 2.

    Gypsum

  3. 3.

    Calcite

  4. 4.

    Fluorite

  5. 5.

    Apatite

  6. 6.

    Orthoclase feldspar

  7. 7.

    Quartz

  8. 8.

    Topaz

  9. 9.

    Corundum

  10. 10.

    Diamond

Other rocks and minerals will have their own typical hardness. You can find their hardness by finding what will scratch them and what they will scratch. These common items have the following hardnesses:

Penny (3.0)

Knife blade (5.5)

Glass (6.0)

Steel file (7.0)

So if glass will scratch your rock and a knife blade will not, your rock must have a hardness between 5.5 and 6.0.

You can do a rough test in the field by scratching your specimen with your fingernail. If it can be scratched, then its hardness is approximately 2.5.

Rocks have many other distinct characteristics, too. A good handbook can help you distinguish these characteristics in the rocks you find and perhaps identify your samples.

Additional Activities

  1. 1.

    Join or visit a gem and mineral club.

  2. 2.

    Check your library for books or magazines on rock collecting.

  3. 3.

    Visit a natural history museum to see mineral collections and learn how rocks are formed.

  4. 4.

    Attend a rock show sponsored by a local gem club.

  5. 5.

    Check government sources for pamphlets or other information on rock collecting.

  6. 6.

    Visit rock shops in your local area or as you travel. Most rock hounds will be glad to share collecting tips.

  7. 7.

    Build display shelves or cases to house your collection.

  8. 8.

    Take a class in lapidary (rock polishing) or jewelry making.

  9. 9.

    Take a geology class through a college or university. These classes often include field trips to local areas of interest.

  10. 10.

    Make gifts, a fireplace, a rock wall, a wishing well, a birdbath, or other garden ornaments out of unique rocks.