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What’s the Difference Between a Stalactite and a Stalagmite?

Stalactites and stalagmites in a cave
Santi Rodriguez/Shutterstock

Stalactites and stalagmites are both natural structures formed from minerals that grow inside caves. While their formation process is a bit different, what truly sets them apart from each other the most is that one grows from the ceiling, while the other grows from the ground.

Visiting Caves

In case you’ve never been to an underground cave: It’s a dark and chilly experience filled with many wonderful and breathtaking sights. If the cave has an underground river, you might even get to see blind fish, creatures who evolved to be sightless in order to save energy within their underground habitat, swimming in streams.

One of the most interesting things to be found within caves are the mineral formations that grow within them, which give rise to many strange and marvelous wonders. No two mineral formations are exactly alike, so it’s quite an adventure to admire them all.

Which One Is Which?

Below is a helpful list that will help you remember how to distinguish stalactites from stalagmites.

  • Stalactites: Not only do stalactites hang on tight to the ceiling so that they don’t fall, but they also have a “c” in their name for “ceiling,” so that tells you exactly what they do.
  • Stalagmites: Not only do stalagmites use all of their might to grow up from the ground, but they also have a “g” in their name for “ground,” so that tells you exactly what they do.

So, both stalactites and stalagmites have hints right in their names to remind you which is which. Also, stalactites have pointed tips and stalagmites have rounded ones, another clear difference between the two that can help you remember that they are not the same.

How Are Stalactites Formed?

All formations in caves start when water seeps through the ground and drips into the cave. (Sometimes water droplets glide down along the underground stone and gradually create a thin sheet that grows from an angle in the rocky wall known as shawl formations.)

The consistent water droplets eventually form a straw-like structure that protrudes from the cave’s ceiling. When the straw gets clogged, the watery minerals stay attached and form the stalactites, which are pointy unless the tips have somehow broken off.

How Are Stalagmites Formed?

When the watery mineral deposits drip from the point of a stalactite to the ground, they begin to form stalagmites. These mineral formations continue to grow up from the ground as yet more mineral deposits are added to them.

While you can find pointy stalagmites, these formations usually have flattened or rounded tips instead (likely owing to gravity). It’s fascinating that as hundreds of years go by, the stalactites and stalagmites keep reaching closer and closer toward one other, sometimes even meeting to create pillars.

One More Cool Cave Creation

Crystals are often formed in caves as well. They can be formed in various ways using saltwater or other minerals. You can even make them at home.

One awe-inspiring cave has been given the not-so-creative name “Cave of Crystals.” Located in Naica, Chihuahua, Mexico, this crystal-filled cave is packed full of selenite crystals of varying sizes, which have all been created over thousands of years because of the activity of gypsum minerals and underground magma.

Yvonne Glasgow Yvonne Glasgow
Yvonne Glasgow has been a professional writer for almost two decades. Yvonne has worked for nutritionists, start-ups, dating companies, SEO firms, newspapers, board game companies, and much more as a writer and editor. She's also a published poet and a short story writer. Read Full Bio »