Geode begins as a gas bubble rising
within lava. Once the lava hardens, the bubble is a void, due to the
earth's natural process of salt equalization where molten silica then
methodically fills the gaseous voids. The various colors of geodes are
determined by trace minerals present within each pocket. The cooling
process will determine the size of crystals that form. The slower the
temperature drops, the larger the crystals become. If the bubble fills
fully, it is referred to as an agate.