What do you have when you break open a rock and discover gorgeous crystals inside? You’ve found a geode. While most people think of rocks as solid, geodes are the surprising exception to that idea. Crack open a geode and instead of a uniform, dull rock you’ll reveal wonderful crystals that can take many forms and display beautiful colors.

What Is a Geode Rock?

Geodes are rounded rocks that have hollow spaces in their centers. These voids are filled with crystals and other minerals.

From the outside, a geode looks like an ordinary, round rock. There’s nothing special or particularly attractive about it. They are lumpy and actually quite ugly looking. It’s only when they are broken apart that their inner beauty is revealed.

How Are Geodes Formed?

You may be wondering how those crystals got into the center of a rock. How geodes are formed is an interesting question, since all geodes are not created in the same way. While geologists aren’t completely sure how geodes form, most of them share similar theories.

Most geodes are formed in volcanic rock. Air bubbles inside the lava flow produce hollow spaces. These hollows create cavities inside the lava as it cools. Over the centuries, water seeps through the lava. Minerals that were dissolved in the water deposit tiny crystals inside the hollow spaces.

Other geodes are formed in sedimentary rock such as limestone, dolomites or shale. These geodes are typically smaller than the ones formed in volcanic rock.

Sedimentary rock forms when sediments, or materials that are in the water, settle to the bottom. The sediments can be rocks, minerals or organic materials like dead trees. As more sediments accumulate, their weight and pressure create layers of rock. Sometimes cavities form within these layers.

Over time, groundwater does what water usually does: it seeks the lowest level. The water seeps through the porous rocks. On its way, it picks up minerals. These dissolved minerals pass through the rock and when they settle in a cavity, they form crystals.

When the crystals are too small to be seen without magnification, they are called chalcedony. Most geodes have a chalcedony shell between the rock and the crystallized minerals inside. Layers of chalcedony cover the inner walls of the geode with a dazzling array of colors, varying from white or gray to blue, yellow and orange.

That explains how the crystals get inside the geodes. But what accounts for all the colors?

The colors of the chalcedony or crystals depend on the minerals that helped create them.

Most geode rocks have quartz or calcite crystals. Usually, quartz crystals are clear or white. When the quartz is purple, it’s called amethyst.

If calcite contains magnesium and manganese, the crystals will be pink. Iron oxides will make the crystals a rusty red color. Titanium creates blue crystals. Nickel or chromium make green. Copper can create blue, green or red crystals, depending on whatever other minerals have been combined with it.

Heat is another variable. If during the formation of the geode, the rocks were subjected to extremely high heat, purple amethyst will become pale yellow or citrine.

It’s important to keep in mind that if you see a geode with very unusual colors, most likely the crystals have been dyed.

Types of Geodes

There are many types of geodes. The type all depends on which mineral or minerals have formed the crystals inside.

Quartz is the most common mineral in geodes, but many others can be found. These include pyrite, calcite, agate, kaolinite, sphalerite, barite, dolomite, celestite, limonite, opal, or smithsonite.

While the color of the crystals is one clue to telling you what type of geode you have, it may not be enough to give you the answer. You might need to use a tool like the Mineral Identification Key to help you know for sure.

Facts about Geodes

Here are some interesting facts about geodes.

The word geode comes from the Greek word geoides, which means “earthlike.”

Geodes are distinguished by a hollow space in their center. If the crystals have formed around a solid nucleus, the result is called a nodule. If the cavity or void is irregular or elongated, rather than being round, it’s called a vug.

One little-known fact about geodes is that they are often wet inside. Some of the water that seeped through the rock might still be there when you open it up.

Every geode is unique, just as every snowflake is unique. The combination of patterns, colors, and orientation of the crystals is different in every geode.The largest amethyst geode in the world is called the “Empress of Uruguay.” It’s over eleven feet tall and weighs nearly 5000 pounds. If you want to see it, for yourself, you’ll have to travel to Atherton, Australia.

Crystal Cave, located in Ohio, is the largest known crystal cave in the world. Technically, it’s a vug, but people call it a cave because of its size: a full 35 feet in diameter at its widest point.

Where Can You Find Geodes?

You can find geodes in many different places in the world. But don’t think you can just chance upon them anywhere. They are found only in places that had the right conditions to create them.

You’re most likely to find geode rocks in deserts, volcanic ash beds, or places with a lot of limestones. Countries that have plentiful geodes include the United States, Mexico, India, Brazil, Madagascar, Namibia, and Uruguay.

Many states in the US are good places to find geodes. The best ones are 

California, Indiana, Utah, Iowa, Arizona, Nevada, Illinois, Missouri, and Kentucky. In the western states, geodes are found in dry valleys or deserts that are volcanic ash beds. In the midwestern states, stream beds are the best places to find geodes.

Some states will list on their websites places that geodes can be found. Websites like findingrocks.com provide a listing of places you can search for geodes. Some of the most popular geode beds in the US include:

· Hauser Geode Beds in the northern portion of Imperial Valley, CA. Also nearby are the North Black Hills Geode Beds and the Cinnamon Geode Beds

· Dugway Goede Beds in western Utah

· The Warsaw Formation in the Keokuk region where Missouri, Illinois, and Iowa meet

If you’re looking to travel farther afield to find some geodes, you could try· Volcanic rock deposits in southern Brazil and Uruguay· Chihuahua, Mexico, where coconut geodes are mined

How to Find a Geode

Start by picking the right site. In the American Midwest, you’ll be looking for areas with warm and shallow water that have a lot of limestones. Limestone is a tan or blueish gray stone with obvious layers.

If you’re in the west, you want to go to an area with volcanic ash beds, like a desert.

Before you go, do a little research and planning. Check out the state website, call the state welcome center or check out rock hunting websites. They may have maps or guides to help you. Gem and mineral clubs are 

another good source of information. These clubs often sponsor trips to go geode hunting. Or you can arrange for a private geode tour. The tour guide can direct you to the best places to find the geodes.

Also, find out what supplies or clothing you’ll need for your trip. Some sites require you to bring your own bucket, shovel or goggles.

Once you’re on site, now the fun begins. Keep your eyes out for rocks with bumpy surfaces. If the rock is smooth, it’s not a geode.

The same goes for rocks with sharp or pointy edges. Leave them alone. You want rocks that are round or shaped like an egg.

Don’t be fooled by the size, either. Some geode rocks are the size of a pea, others are the size of a soccer ball or even larger. What you want to do is check the weight. Since geodes have hollow spaces in the middle, they will weigh less than other rocks of the same size. So, compare the weight of the rock you think might be a geode with another one of the same size. If it’s lighter, there’s a good chance you’ve found a geode. You can also shake the rock gently to hear if anything is rattling around inside.

Most likely you’ll need to do a little digging. Use a shovel to scrape the top layer of dirt, ash or sand. Wind or rain could easily move dirt or sand to cover geodes. If you’re on a tour or sponsored trip, the guides will be able to point out good spots to dig.

Some people like to open their geodes as soon as they find them. If you’re impatient to reveal the inside, your kids can’t wait, or you don’t care about a clean cut, you’ve got a few options. One is just to hammer the geode with another rock. If you put the geode in a sock before you do this, it will keep the pieces from flying all over. Don’t hammer too hard, or you might smash the geode and its crystals.

If you’re more concerned about a clean cut, you can use a hammer and chisel to carefully crack the rock open. For more precision, wait until you get home and use a saw or pipe cutter. For the most precise, clean cut, take your geode to a rock store or other professional. They’ll give you an even cut for a small fee.

What Are Geodes Used For?

There are many things geodes are used for. Because of their beauty, many people use them simply as decoration. They can be used as paperweights, or, if you have a matching pair, as a set of bookends.

Very small geodes can be made into jewelry, such as earrings or pendants. Large geodes have been made into tables by covering the open side of the geode with a piece of glass.

Other people use the geodes for meditation. Still, others try to tap into the geodes’ metaphysical properties. The idea is that certain crystals are linked to certain properties. If, for example, people who want love and protection in their lives, will use an amethyst geode to help them get these qualities in their lives.

Still, others use geodes to work with two-dimensional energy to connect with spirit energy. The energies shift depending on which stone is used and where it is being placed. This can be done in for personal or business reasons.

For example, citrine is a money stone. Placed in your wallet or bank bag, or next to your cash register or credit card machine, the stone can attract wealth or help you maintain it.

Amethyst is another example. This stone relieves anger and brings inspiration, luck, connection with spirit, and positivity into your life. Many people put amethysts in every room of their homes or businesses. The energy will shift whether you believe it will or not, just by having the stones present. Proper placement of the stones will allow the energy to transform the space and give you the positive benefits amethyst bring.

If you want to tap into the energy that can help you increase wealth or happiness or have questions about how to choose and place stones, call McCall consults. We’ll be happy to show you how to use stones to tap into the energy that can transform your life.