Iowa also has no state mammal. But it does a have a state rock: the Geode! So let's ask about that. What is by far the most common mineral found in geodes?

Geode comes from the Greek word for "earthlike." Macrocrystalline quartz is the most common mineral in geodes, but they can also have many other crystals, like kaolinite, sphalerite, millerite, barite, celestite and dolomite. The variety of colors in a geode is the result of impurities.

Asked by Tom Cohen · Last updated 5 years ago · 0 views