Calthemite

Calthemite is a big word for something that grows on the walls of caves. You know how you see icicles hanging off of things when it's really cold outside? Well, imagine if those icicles were made out of rocks instead of ice, and they grew on the walls of a dark, damp cave instead of outside. That's what calthemite is!

Now, these rock icicles aren't really made out of pure rock. Instead, they're made of minerals that slowly build up over time. These minerals dissolve in water and then get left behind on the cave walls as the water drips down. When this happens again and again over a long time, the minerals start to form into cool shapes like stalactites, stalagmites, and calthemite.

Calthemites are different from other cave formations because they don't grow in straight lines like stalactites and stalagmites. Instead, they can grow in all sorts of directions and shapes, kind of like a tangled spiderweb made out of rocks. Calthemites can be really pretty to look at, but scientists are still studying exactly how they form and what they can tell us about the history of the caves they grow in.