Opening Geodes and Cleaning Geodes

Caution: Always wear eye protection when working with geodes.

Check your geode for any hairline cracks. If you find one, take a flat tipped screwdriver or a small chisel (depending on the size of the geode) and carefully insert it into the crack. Twist the screwdriver/chisel tip and try to get the geode to separate, if it does not separate then try tapping the screwdriver/chisel lightly with a hammer or the palm of your hand, moving the screwdriver along the crack and hopefully it will open into two nice fitting pieces.

Many of the Keokuk geodes will be hollow so you must use care when opening to avoid smashing the geode into numerous pieces. Pick up your geode and if it feels light for it's size it probably has a very thin shell and is mostly hollow ( a baseball size geode will normally weigh about one pound about the weight of a regular can of soup). While wearing gloves to protect your hand, hold the geode in the palm of your hand, strike it lightly with a flat headed hammer (a snap wrist action works best). Continue striking until a crack appears then insert a small screwdriver into the crack and pry open your geode. If 15 strikes of the hammer does not cause a crack increase your striking force a little and continue. If 15 more strikes of the hammer doesn't cause a crack - use the method below.

If there is no visible crack in your geode and its weight seems to be appropriate (according to the example above), your geode probably has a small cavity or is mostly solid.  Draw a line around the circumference of your geode. Take a chisel and a large hammer and tap along your line until a crack appears, then use the above technique to open it.

Another method is to lay the geode in a soft depression on the ground. . Look for any large cracks, hairline cracks or weak spots. When you have decided where you will apply pressure, use a medium weight hammer and center punch. Put the punch in a spot most likely to keep if from sliding off, and hit it several times; easy at first, then harder. If three or four blows do not open the geode, repeat in other spots until a crack does appear. Then use a screwdriver to pry the geode apart.

Of course, the easiest method is to put your geode in an old sock and just strike it hard with a good size hammer. Sometimes, if you are lucky, the geode will split right in two but most often it shatters into numerous pieces. 

Another trick to help opening your geodes is to let them sit in water for about 1 week before opening. I am not a chemist, so I do not know why this helps but it does make the geodes easier to crack. If anyone knows the chemistry involved here and why this works, please e-mail me and I will add your ideas to the rockhound information page.

  Perhaps oxygen in water( H2O ) combines with the minerals in the geode to make opening easier. If you think about how water running over rocks shapes and erodes them over thousands of years, the softening is probably a real early effect of water. Also hydrogen peroxide( H2O2 )breaks down anything it contacts. It only has 1 more oxygen than water - . That is my thinking any way.
Rockhound Tip provided by:
Donna & Evan Sheets...... Washington

Cleaning Geodes

There are many different ideas and tricks when it comes to cleaning geodes.

 
 CAUTION: First before doing anything, visually inspect the inside of the geode and check for microscopic minerals e.g. calcite, geothite, millerite, kaolinite. Some small crystal inclusions will be damaged by scrubbing and or chemicals. 

We simply wash them in plain water with a bit of laundry detergent, then let them set in a tub of water with 1/4 cup of ordinary household bleach for two days. This cleans most of the heavy grit off the geodes. 
Finally we clean each geode with and electric toothbrush and ordinary denture cleaner, carefully covering all the crevices with the denture cleaner and brushing till all the grit is removed and the crystals are clean and bright.. This is at times a long and tedious project but it has worked for us thousands of times.

Other methods include: Using high pressure water spray (at the car wash), soaking the geode in wood bleach. We found the wood bleach to work well on quartz, but only soak them for a few hours to avoid any damage to the geode.
 CAUTION: Wood bleach can harm calcite crystals.

Wash geode thoroughly with warm water after cleaning. Add baking soda to the wood bleach before disposing to neutralize the solution. 
 WARNING - Wood bleach is toxic, wear eye protection and gloves to avoid injury. Do not use wood bleach in metal containers, it can eat through them.