Polished Geode Half With Quartz, Agate, and Cristobolite

A stunning and highly polished half of a Las Choyas (coconut geode) from the Chihuahua State of Mexico. This particular specimen has beautiful blue-grey agate, quartz, and the quartz polymorph cristobolite (the little orbs). A visually stunning specimen! This particular type of geode, how did it form? These were once vesicles, bubbles that formed in lava as it was cooling that never quite made it to the surface. This left the perfect cavity for water to deposit crystals over time.