Break Your Own Geode. Discover what's inside.

How to Crack a Geode

January 2024

Written by Stalac-Tate & Holly

Discover the world of geodes! These quartz-filled rocks seem unassuming on the outside but a treasure within. It’s fun to learn about them and even more fun to break them open!


Learn about the secrets of this unique rock! This free talk about geodes is geared mainly toward children and families, but anyone can participate. After the talk, the speaker will demonstrate how to open a geode and one lucky audience member will receive a free geode.


A Geode appears to be an ordinary concretion of sedimentary or volcanic rock, but they were a hollow cavity at one time that crystals have grown inside of. Some Geodes fill in completely with minerals while others are still hollow. If you break open a Geode, you will find a treasure of agate, minerals, or crystals resembling a miniature cave.

What in the World is a Geode?

A geode is nature’s secret treasure box!

Appearing to be an ordinary rock on the outside, geodes can be broken open to reveal a trove of beautiful crystals of all shapes, colors, and sizes!


The largest amethyst geode in the world is The ‘Empress of Uruguay’ Over three meters tall (that’s eleven feet) and weighing two and a half tonnes. It is located in Atherton, North Queensland, Australia.

How Does a Geode Form?

Geode formation is a naturally occurring process between groundwater and the surrounding rock.

  1. A hole forms in bedrock. For igneous geodes, this hole is formed from air bubbles becoming trapped in magma. For sedimentary geodes, this hole forms from either the dissolution of already-there materials or from the decay of organic matter like sticks or shells within the rock.
  2. Mineralized water then begins to seep into the cavity, slowly building up layers of crystalline minerals over hundreds, thousands, or even millions of years!
  3. The color of the crystals depends on what minerals were in the area that the geode formed: anything from white to purple to orange to even black is possible!
Photo of our Amethyst Cathedral Pair


Agates – the smooth, banded, and often colorful sliced stones – are also a type of geode! They are a form of microscopic quartz crystal that deposits in beautiful layers that can be readily dyed for more vibrant colors!

What Will You Discover?​

Crystal size and color vary between each and every geode, guaranteeing you a one-of-a-kind find!

Quartz is one of the most common examples of crystalline minerals that will grow within a geode.


Geode has been Iowa’s Official State Rock since 1967. Learn more here <<<<

How to Break-Your-Own-Geode at Home!

  1. Put on safety goggles
  2. Grab a chisel and hammer
  3. Wrap your geode in a sock or cloth
  4. Set the geode on a hard surface such as concrete.
  5. Place the chisel/screwdriver in the middle of the geode, and tap it very gently a few times with the hammer. Watch your fingers!
  6. If it hasn’t cracked yet, turn the geode a quarter turn and do this again.
  7. Continue to move along the circumference of the geode until you see a crack form all the way around, then pull the two halves apart.
Photo of broken open geode. An activity to do at this Must See Destination in Wisconsin

How to Break Open a Geode Video!

Play Video about Kids gathered around a cracked open geode