What Are The Differences Between Stalactites And Stalagmites?

Stalactites hang from the ceiling in a cave.
Stalactites hang from the ceiling in a cave.

What Is A Speleothem?

A cave is an underground opening that is usually large enough for humans to enter. Caves are generally formed by weathering, which is the erosion of rock by wind or water. A cavern is a special type of cave that produces speleothems, or cave formations. Speleothems are found in a wide variety of shapes and sizes, resulting from dripping, pooling, condensing, seeping, or flowing water. Two of the most well-known types of speleothems are stalactites and stalagmites. This article takes a look at the difference between the two.

What is a Stalactite?

A stalactite is a speleothem that hangs from the ceiling of a cave or cavern. It often takes on an icicle-like shape.

Word Origin

The word stalactite comes from the Greek word stalaktos, which means “to drip”.


As previously mentioned, stalactites hang down from the ceiling of the cavern, which means that they point downward towards the floor.


Water condenses and collects on cavern ceilings. This water contains soluble material, like minerals, mud, sand, pitch, or sinter. Additionally, as the water moves through the rock to collect on the cavern ceiling, it extracts carbon dioxide gas. This action creates a carbonic acid that is able to penetrate the rock, leaving behind an area of calcite. Calcite is a carbonate mineral or polymorph of calcium carbonate. As water continues to permeate the cavern ceiling, it continues to drip over the preexisting area of accumulated calcite. This continuous drip adds more calcite to the location, which, over time, begins to take on the icicle-like appearance. Stalactites continue to grow in length as more and more calcite collects. These formations grow at an extremely slow rate. Research suggests that it can take around a thousand years for under 10 centimeters to form. Some stalactites have been radiometrically dated at more than 190,000 years old.

Types Of Stalactites

There are several types of stalactites, including concrete, ice, lava, and limestone.

  • Stalactites can form on concrete, located near plumbing or under bridges. This type of stalactite tends to form faster than those found in caverns. These are not considered speleothems.
  • Ice stalactites are found in cold temperatures. They are more commonly known as icicles.
  • Lava stalactites form within lava tubes where active lava is present. The formation process is the same as previously described, although much faster, occurring in a matter of weeks or hours. These stalactites do not continue to grow once the lava is no longer present.
  • Limestone stalactites are the most common and found within caves and caverns.

Longest Stalactite In The World

The longest stalactite in the world is located in the Jeita Grotto of Lebanon, about 11 miles north of Beirut. This grotto is a system of 2 connected, limestone caves that run for 5.6 miles. The lower section of the cave was discovered in 1836 and can only be accessed by boat. In 1958, scientists discovered the upper section, which is located 200 feet above. This section of the cave is open to tourists. It is also home to the longest stalactite in the world; found in the White Chamber, it measures 27 feet in length.

What Is A Stalagmite?

A stalagmite is a speleothem that is located on the floor of a cave or cavern in a mound-like shape. The top of the mound continuously collects mineral deposits that help the stalagmite grow in height over time.

Word Origin

The word stalagmite comes from the Greek word stalagmites, which means to drop or dropping or trickling.


As previously mentioned, stalagmites rise up from the floor of the cavern, which means that they point upward toward the ceiling.


Stalagmites are most commonly located beneath stalactites. This is because the same water that forms stalactites is not contained on the ceiling. This water falls to the cavern floor, where it creates another concentration of calcite. Rather than form the typical icicle shape, however, the stalagmite-forming drips first create a mound-like shape. As more water falls, it continues to slide down the sides of the mound, creating wider and taller stalagmites. Its growth rate is similar to that of limestone stalactites, taking as long as a thousand years to form 10 centimeters or less.

Types Of Stalagmites

Like stalactites, stalagmites have 4 distinct variations: concrete, ice, lava, and limestone.

Concrete stalagmites may occur on concrete floors, under concrete buildings, or under concrete bridges. These occur when concrete begins to degrade and release calcium ions. Concrete stalagmites develop quickly and are usually only a few centimeters in height.

Ice stalagmites occur when water seeps into a cave and falls to the floor, where the temperature is below freezing.

Lava stalagmites are similar to the previously mentioned lava stalactites. They form in lava tunnels where there is active lava. Once the lava is gone, these stalagmites do not continue to grow.

Limestone stalagmites are the most common and occur in limestone caverns with specific pH conditions. Touching or otherwise disturbing these formations will stop their growth as skin leaves behind oils that create a barrier, preventing additional minerals to concentrate.

Largest Stalagmite In The World

The largest stalagmite in the world is located in the Martin Infierno Cave in Cuba. It measures around 204 feet in height. This cave, which is 2,600 feet long, was discovered in 1967 in the south-central region of the island in the Yaganabo Valley. In order to protect this site and the still-forming stalagmite, the government of Cuba declared the cave to be a National Monument in 1990. Some scientists, however, believe the cave needs additional protections. Their argument is that this distinction serves to draw attention to the area, bringing more tourists and potentially damaging this natural formation.

After thousands of years, stalactites and stalagmites may grow significantly. So much so, that eventually, the tip of the stalactite and the top of the stalagmite will grow together. When this happens, scientists refer to the formation as a column.

To remember the difference between stalactites and stalagmites, speleologists and other cave enthusiasts often use the following phrase: “Stalactites hold tight to the ceiling and stalagmites might reach the ceiling one day.” Another way to remember the difference is that the “c” in stalactite stands for “ceiling”, while the “g” in stalagmite stands for “ground”.


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