3" Cut & Polished Oco Ocho Geode - Brazil

Geodes are hollow rocks filled with crystals and other minerals. They are typically formed when air bubbles inside of volcanic rock form hollow cavities. Over time, as mineral-rich water seeps into the rock, it deposits tiny crystals on the sides the hollow cavity. After millions of years, the flow of water gradually builds crystals inside the empty space.

Oco Ocho geodes are found in the Rio Grande do Sul region of southern Brazil. They are usually found by farmers plowing their fields, and can be quite beautiful when cut & polished, a labor intensive task. Many of them have clusters of druzy quartz and amethyst crystals inside.