What is cactolith?

As an AI language model, I don't have personal experiences but here's some information about Cactolith:

A cactolith is a rare geological formation that is believed to have been formed around 25 million years ago. It consists of a cylindrical mass of igneous rock (usually granite) that is surrounded by a sheath of sedimentary rock (usually sandstone or shale).

The word cactolith comes from the Greek words kaktos (meaning cactus) and lithos (meaning stone). The formation was so named because it often resembles a giant cactus in shape.

Cactoliths are found most commonly in the southwestern United States, particularly in the Mojave Desert of California and in Arizona. They can also be found in parts of Mexico and Australia.

The exact formation process of cactoliths is not completely understood, but it is believed that they were formed from magma that intruded into sedimentary rocks and cooled slowly over a long period of time. The surrounding sedimentary rocks were then eroded away, leaving behind the hardened igneous rock in the shape of a cylindrical mass.

Cactoliths are a fascinating natural phenomenon and are often studied by geologists and other scientists to learn more about the earth's history. However, they are also extremely rare and difficult to find, so many people consider them to be a treasure of the natural world.