How to Crack Open a Geode

Co-authored by Sam Lagor, MSc

Last Updated: May 12, 2022 References Approved

If you've discovered a geode (a rounded rock formation with crystals or banding inside), you'll want to crack it open as safely and neatly as possible. Every geode is unique, and could hold anything from clear, pure quartz crystals to rich purple amethyst crystals, or perhaps agate, chalcedony, or minerals like dolomite.^{[1]
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Research source} Fortunately, there's more than one way to crack open a geode...

Steps

1
Put on safety glasses before attempting to open a geode.^{[2]
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- It may help to wear a pair of gloves, too.

Method 1

Method 1 of 5:

Sledgehammer Method

1
Put the geode in a sock and set on the ground.
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Take a small Sledgehammer or a rock hammer (preferably not a construction hammer, such as a claw hammer) and strike the top center of the geode. A couple of strikes might be required to fully crack open this rock. This is likely to result in the geode fragmenting into more than two pieces, but it is the most suitable method for kids, though not recommended for particularly valuable/rare geodes.^{[3]
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- Rock hammers are made with reinforced steel, making them stronger than your typical carpenter hammer.

Method 2

Method 2 of 5:

Chisel Method

1
Take a rock or masonry flat chisel, hold at top center of rock, then strike with a hand-held sledge hammer. Tap lightly, as to score the rock only.^{[4]
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2
Rotate rock a bit, then strike again to create a line around the circumference of the stone.
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Repeat, as necessary, until the rock splits open. Patience is key; if the geode is hollow, it will probably take a few minutes of gentle scoring to open it, but if the geode is solid, it'll take longer.^{[5]
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Method 3

Method 3 of 5:

Striking Method

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Strike geode with another larger geode. This only really works if you control the striking rock in the palm of your hand. Only use this method on small, golf-ball-sized geodes.

Method 4

Method 4 of 5:

Cast Iron Pipe Snap Cutter

1
Use a cast iron pipe snap cutter. This common plumber's tool can aid you in splitting a geode symmetrically, that is, into two equal halves. Wrap the tool's bicycle-type chain around your geode.^{[6]
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Feed the chain into the tool securely around geode.
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Pull down the handle to apply equal tension around the geode. It should crack smoothly all around. (This is the least destructive method that displays a geode in a natural form.)

Method 5

Method 5 of 5:

Diamond-Blade Saw Method

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Use a lapidary diamond-blade cutting saw to slice the geode open, or into halves. (Note that oil can damage the interior of some geodes.)

Community Q&A

Question

Why should I use a sledgehammer?

Community Answer

It is not recommended to use a sledgehammer as it will smash the geode into many pieces and can destroy the crystals/formations inside. Hammer and chisel is a much better method.
Question

How are geodes made?

Community Answer

Over many years, mineral water seeps into the rock. As the water makes its way through the rock, the minerals get sifted out, and are left behind in the rock in a crystalline formation according to the type of minerals in the water.
Question

Do I have to put it in a sock when breaking it open?

Community Answer

No, but the method provides a good measure of safety by preventing the pieces from flying all over the place.

Warnings

Always be careful and follow general safety procedures for rockhounding and tool use. Be mindful of any folks (or animals) observing you cracking open your geode, as rock shards you create may fly towards the onlookers, and injure them. With safety in mind, please enjoy your geodes.

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