“....Our Eggzilla mine is on private property in Luna County, NM. These thundereggs were formed 20-30 million years ago when the Rio Grande rift valley caused thousands of volcanoes in southern New Mexico. This is where the volcanic flows originate that we dig in. We started digging this mine in October 2011. The name of it is 'Eggzilla' because of the substantial size of the thunderegg/geodes coming out of it.
That in itself would usually be enough but it is the inside of these incredible thundereggs/geodes that will surprise you. These geodes contain quartz pockets, smoky quartz, clear and white quartz. The agates in these geodes vary from black, white and blue. The pseudomorphs inside are also incredible and very rare. Some of them also contain Zeolites in black and white.
Some of the geodes also have pockets of Jasper. The really rare and great ones contain some of all of the above. Another exciting thing about these geodes is that some flouresce beautiful greens, blues and red's...”
Written by Lori Coleman on the website of his "Spanish Stirrup" rockshop in Deming, New Mexico.
The Pseudomorphs in the Interior of the Eggzilla Thundereggs are usually curved. This distinguishes them from the Lava Cap Thundereggs, coming from a nearby site. This Pseudomorphs lead also to associations. The "bird stone" is a fantastic example for this.