Rocks and Minerals for Kids: How to Get Started

Looking for a fun hobby to introduce your kids to? Have you ever considered rock collecting? Rock collecting (or “rockhounding,” as many in the hobby call it) is very popular these days. I started rock collecting when I was about five years old and I’m still doing it today.

The first thing you are going to need to start a rock collection is a few rocks. There are two ways that your kids can start their collections: they can find them themselves or they can buy them from places like museum gift shops.

Finding nice specimens in the field is not as complicated as you might think. If you have a gravel driveway then that can be your first place to look. Look for anything that stands out from the other pebbles in the driveway and save it as a specimen. Another great place to search is a farm field. Every time a field is plowed a lot of rocks are heaved up with the soil and will just sit in the field until someone finds them or they are plowed back under. Just ask a farmer if you and your children can spend a few hours searching through his field. In most cases he’ll be more than happy to let you take some of those pesky rocks away. You can also search for public accessible rock-collecting sites on the Internet.

Now that you’ve found some places to go rock hunting you can start planning your trip. Your children will each need something to carry their rocks home in. A cloth bag works really well for this purpose. If some of the specimens are fragile you can wrap them in toilet paper to protect them from harm. You may also want to take a pad of paper and a pen with you so that you can record the name of the site if you want to remember that later.

Once you have found a few nice specimens and brought them home they may need to be cleaned. If they have any dirt on them your kids can scrub that away with old toothbrushes and soapy water. A note of caution: it is a good idea to test the rocks by wetting the corner of the specimen before cleaning them. Some rocks will actually dissolve in water!

After the specimens are cleaned you can store them. I use plastic beading boxes with twenty compartments each to house my collection. This keeps the rocks and their labels together (I will talk more about the labels shortly) and allows you to store them in a compact space. These boxes cost less than five dollars a piece.

Now it’s time to identify the rocks. For this you will need a good rock and mineral identification book. These books explain how to identify minerals using their color, the streak test, the hardness test, and a lot of other techniques. Such books are a very good investment. You may want to consider purchasing a fossil identification book as well, since your kids may find a lot of fossils.

The Zeolites: A Family of Useful Minerals

The term zeolite denotes a family of minerals with similar chemical structures. They are all aluminum- silicate minerals that have crystal structures which resemble honeycomb. Zeolite minerals are often found in vesicles inside volcanic rocks, especially basalt. There are about fifty minerals in the zeolite group.
The honeycomb-like structure found within the zeolites includes a lot of tiny tunnels and pores that allow water to pass through the mineral without affecting its crystal; and these pores are all of a uniform size. Now ask yourself: does it seem that something like this could occur by chance or do you think it points to the design of a Creator? It’s something worth thinking upon.
Because of the properties that I mentioned above, zeolite minerals are often used to filter very small particles out of air and water. They can also hold water like sponges so they are used thus and in place of potting-soil in some agricultural applications. Zeolites are used to clean up oil spills and radioactive waste as well.
Zeolite minerlas are found in many different countries far too numerous to mention here. I plan to write about some of the members in this family of useful minerals soon and their properties and locations can be discussed on an individual basis.

Antimony's Toxic Legacy

When I made my last post I said that I planned to talk about the metal antimony’s toxic legacy. I researched the topic and found nothing concerning the symptoms of antimony poisoning save that antimony compounds attack certain tissues in the body. I have read that consuming large enough doses of antimony or its compounds is lethal. In fact, antimony’s very name is said to come from a story in which a monk named Valentinus added stibnite to the other monks’ food in an attempt to help them gain weight. Unfortunately the stibnite did not have its desired effect and the monks died. After that it was called anti-monachium which means “against monks.”
So where does this leave our shiny, gray mineral stibnite? Well if you were to eat a large enough quantity of stibnite you would die, but handling the mineral isn’t the same as consuming it. I have always read that you should wash your hands carefully after handling stibnite. Don’t let young children touch it--keep it out of their reach. I keep mine in a plastic “perky box” to minimize contact with it.
Stibnite is a beautiful mineral, one that I am happy to include in my collection. It should not be feared, but rather respected. Follow the safety rules that I have mentioned above and use common sense when collecting stibnite.

Stibnite: Toxic Beauty

The metal antimony was once called stibium, which is why it is represented by an Sb on the Periodic Table of Elements. Stibnite’s name stems from the fact that it is an ore of antimony.
Stibnite is a steel-gray or lead-gray mineral that has a metallic luster (although it can tarnish, turning black) Stibnite’s crystals are orthorhombic and are usually blade or needle-shaped. Its crystals are slightly flexible so they can be bent or twisted. I wouldn’t do this with any good specimen, but it could be a helpful test to help identify the mineral. Stibnite measures only a 2 on the Mohs scale of hardness.
Stibnite is still the main ore of antimony, which has been used since ancient times (though for many years it was confused with lead) Today antimony is mixed with other metals to form alloys that are used as coverings for cables and in car batteries. Stibnite itself is used in the making of matches, percussion caps, and fireworks.
Stibnite is found in places like: Japan, Serbia, Macedonia, Romania, Peru, California, and Nevada.
A final word of caution: stibnite is a poisonous mineral! Antimony is toxic and it imparts this property to its ore. Always wash your hands carefully after handling stibnite. This topic will be discussed further in my next post.

Anhydrite: Warning! Keep Dry!

The word “anhydrous” means “lacking water.” So, when gypsum looses the water molecules that help make up its chemical composition “anhydrite” is an apt name for the new mineral that results.

Anhydrite commonly forms when gypsum dehydrates, but it can form in other ways. It is often found between layers of gypsum and even between gypsum and halite. Because it usually forms when gypsum dries out the layers of anhydrite are often contorted.

Anhydrite crystallizes in the orthorhombic crystal system, but it is usually found in massive or fibrous habits, the latter looking a bit like satin-spar selenite (a variety of gypsum that you can read about in my March 17, 2011post Gypsum: The Mineral About the House) Anhydrite can be distinguished from gypsum by the fact that it is a little harder. Anhydrite is usually white or colorless, but it can also be lavender, reddish, bluish, or gray.

I’ve already stated that gypsum becomes anhydrite when it looses its water, but if the anhydrite absorbs water then it will become gypsum once again. Because of this, anhydrite can be ground into a powder and used to make concrete and plaster of Paris. This property also makes anhydrite difficult to find. Since it so easily reverts to gypsum, anhydrite tends only to be found deep underground where it won’t be exposed to much moisture.

Anhydrite can be found in such places as: Mexico, Cuba, Peru, Chile, Canada, Zaire, and the American states of: Alabama, Michigan, Louisiana, and Texas.

I hope that you’ve enjoyed this piece about anhydrite. I have one final note for collectors which concerns anhydrite’s relationship with gypsum: if you want to collect the stuff it is a good idea to keep it in an airtight case with some silica gel. Otherwise your anhydrite specimen might revert to gypsum!