Geodes were once bubbles in lava. Over time the surrounding minerals penetrate the bubble and crystals begin to form within.

The type of crystal that forms inside of a geode is determined by the type of minerals that surrounded it at the time of its formation.

In the case of the Las Choyas Geodes, so many different types of surrounding minerals were present that it is almost impossible to predict what types of crystals you can find inside. This is why the Las Choyas Geodes are so entertaining to break open. It’s a surprise each time!

Trancas Geodes will glow under a black light. These geodes are also known as the Chihuahua Geode. They tend to look like miniature caverns. Stalactites and stalagmites are common. The primary crystal is white quartz and the secondary crystals can be fluorite, quartz and calcite.

Geodes are found whole imbedded in some type of volcanic tuff.