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Cave Formations

Are those cave formations stalactites or stalagmites? Here’s how to tell the difference…


stalactite grows from the cave ceiling, so it has to hold on “tite”.


stalagmite grows from the cave floor with all of it’s “mite”.

Now that you know which is which, you may be wondering how they got there. Cave formations are known to cavers as speleothems. They are formed by mineral-rich water dripping and seeping through caves. This water deposits minute amounts of minerals, usually calcite and aragonite, over thousands of years to form these speleothems. 

The adventure of seeing these speleothems is one of the main attractions of cave exploration. Because they take so much time to form, preservation is very important. Because oils in your skin can create a barrier to the minerals being deposited, it is very important not to touch a formation as this can “kill” the growth of that formation.

When touring or exploring a cave, it may be tempting to take a piece of it home with you, but remember that these formations are irreplaceable. It is not only a federal crime in many instances to damage a cave but it is also a crime against nature.

So what other speleothems are there? Many more, and like a snowflake, no two are exactly alike.


Flowstone are sheet-like speleothems that form on cave walls or floors. They often look like frozen water.

Rimstone Dams

And some formations act as dams to hold water back and create pools. These are called Rimstone Dams.


Some formations look like hanging curtains or drapery.


Some curtain formations have colorations that make them look like bacon. I get hungry just looking at them! No, I didn’t take a bite out of this one.


Another  common speleothem that looks like food is cave popcorn, which are clumps of calcite that look like popcorn. It is sometimes called cave coral because it also resembles sea coral.

The most beautiful of all cave formations have to be cave crystals. These are formed from calcite or aragonite.


Small, needle-like formations are called frostwork.

Dogtooth Spar

Dogtooth spar is a larger crystal formation that, as it’s name implies, resembles dog’s teeth.

Giant Naica Crystals

Unbelievably large gypsum crystals were found at the Naica mine in Mexico.

Cave Pearls

Cave pearls are a fascinating find in any caving adventure.

These speleothems not only look similar to the pearls found in oysters but are formed in much the same way.

I hope this gives you a good idea of what you can expect to see in caves. This is not an exhaustive list but covers the more common and/or interesting formations.