15 Ways We Use Rocks

For rockhounds, rocks can be fascinating even if they aren't useful. Thundereggs, agates, quartz—they all have cool names and they're shiny.

Throughout history, however, rocks have been used for many, many different purposes.

In my previous post, I mentioned my family's rockhound neighbor, back when I was a kid. This neighbor taught one of my brothers how to polish rocks and introduced my family to a variety of different types of rocks.

One of those rocks was obsidian. 

Obsidian has fascinated me ever since then—it’s a rock, but it’s also glass?

As I’ve learned more recently, obsidian isn’t just a plain, black, glassy rock. It can have snowflake patterns or rainbow colors. Because it is glass, obsidian breaks in a curving “conchoidal” fracture.

And because it breaks into pieces with thin edges, it’s been used to create knives, arrowheads, and other sharp tools.

Rocks like obsidian were one of the first materials that humans used to make tools, but humans have used rocks for many other purposes as well.

An illustration from Can a Rock Grow? showing a knife made from obsidian.

• Rocks can be tools—humans have used rocks as knives, hammers, axes, mortars to grind food, and many other kinds of tools.

• Rocks can be landmarks—if you grew up playing Oregon Trail, you probably remember passing Independence Rock and Chimney Rock along the way. Mountains, boulders, and other unusually shaped rocks have helped people mark trails all around the world.

• Rocks can be a sacred area—not all landmarks are sacred areas, but many cultures revere certain landmarks as special places. Some of these rocks include Uluru in Australia, the Black Hills in South Dakota, and the Temple Mount in Jerusalem.

• Rocks can be monuments—cultures from around the world have used rocks to build statutes, temples, and other monuments to commemorate their rulers or major events like battles.

• Rocks can be records—one of the most well-known historical records, the Rosetta Stone, recorded a legal decree in three different languages. An early Egyptologist compared the languages on this stone and use it as a tool to decode the secret of hieroglyphs.

• Rocks can be a canvas—ancient humans used rocks as a canvas to create cave paintings, petroglyphs, and even human handprints.

• Rocks can be a home—from European castles to Anasazi cliff dwellings to modern buildings with marble facings, people have used rocks as a sturdy, durable building material.

• Rocks can be barriers, or bridges—as a building material, rocks have been used to create the Great Wall of China and the Bridge of Sighs in Venice, as well New England stone walls around pastures and fields. Today, stones are still used around the world to build backyard terraces.

A terraced wall made of basalt blocks.

• Rocks can be a game—ancient games like Mancala and Go used stones as their playing pieces. Anyone with a supply of small stones could create their own set to play these games.

• Rocks can be mosaics—while later mosaics often used special tiles, early pavement mosaics used pebbles in different colors to create patterns. Some pavements even showed events or figures from mythology.

• Rocks can be ornaments—throughout history, people have used precious gems and semi-precious stones to decorate jewelry or other ornaments. In some cases, these ornaments were even used in place of money.

• Rocks can be tools for cleaning—while washing up with a rock may seem strange, rocks have been used for cleaning throughout history. In the Philippines, panghilods are smooth scrubbing stones that may be used bathing or for exfoliating.

• Rocks can be history—records like the Rosetta Stone can be used to decipher human history, but geologists use natural rock formations to uncover the Earth’s history, while fossils can show the history of life here on Earth.

A fossilized shrimp from a museum display.

• Rocks can be warmth—coal is fossilized plant material. When coal is burned, the rock is transformed into heat that can warm a house or produce electricity in a power plant.

• Rocks can be a gift—ancient kings might have used diamonds and rubies to reward their followers, but a gift can be as simple as a painted rock or a bit of mica from a special hike.

Ready to use some rocks in craft projects? 

Try one of these activities, or put together a party, complete with a rock-themed snack!

A small rock with a melted crayon drawing using orange and blue colors.

• Melted Crayon Rocks: Painted rocks are very popular now, but melted crayon rocks is a fun variation on that project. For this project, start by warming the rocks so that when kids color on them with a crayon, the crayon melts from the heat. We warmed our rocks in the oven with the temperature set to low (overheating rocks can cause them to explode, so this is a bit dangerous). Left Brain Craft Brain suggests using a candle warmer instead. Since the rocks will be warm, you might want to give your kids a rag or an old winter glove to protect their fingers if they need to touch the rock while coloring it. You can use beeswax crayons to create a biodegradable art project, or you can coat the rock with collage glue to protect the colors.

• Rock Games: Mancala is a two-player game that starts with groups of stones arranged in two rows. You could play this game outside with gravel, digging small holes for the pockets, or you can use your kids’ rock collections and adapt an egg carton to hold the stones using the instructions from Math Geek Mama. For a different game, play tic tac toe with stones painted with two different colors or patterns, like this bees and ladybug set from Red Ted Art.

• Soap Carving: Soapstone is a popular material for rock carving, since its soft and easy to work. Carving soapstone takes a special set of tools, though. If your kids aren’t ready to use sharp tools yet, you can use a craft stick to carve a bar of soap, as suggested by There’s Just One Mommy.

Small rocks arranged into a rainbow on a stony beach.

• Rainbow Rocks: Next time you explore a beach or another area with lots of small stones, challenge your kids to look for different colors of rocks. Use these rocks to create a rainbow (or even a mosaic). This is a fun way to compare colors and notice just how many different colors rocks can be.

• Rock Party: When all the crafts and games are over, celebrate with with a rock-tastic treat! There are plenty of different ways to show the rock cycle, but Elementary Shenanigans uses rice crispy treats, smores, and chocolate sauce to show how sedimentary, metamorphic, and igneous rocks form.

You can also find a set of fun science activities here. Most of these projects use common household supplies, so they're very easy to set up and will help kids explore how rocks change.

Want to add some reading fun to your rock party as well? My picture book, Can a Rock Grow? introduces young readers to the rock cycle and the different ways that rocks change over time. It's free on Kindle Unlimited, or you can preorder a hardcover here.