Physical Geology 2004 example of an Anthodite formation. This picture was taken in Skyline Caverns, which is one of the only public places you can view them. The picture below is also another photo taken from Skyline Caverns of the "Reflecting Pool", an optical illusion which forces the viewer to believe the pool of water is many feet deep, when it is only a few inches deep.




The shot above is another example of the unique Anthodites of Skyline Caverns. The shot below is an example of a helictite.

This is an Aragonite formation found in Lechuguilla near Carlsbad Caverns in New Mexico. Aragonite is similar to Calcite except for the crystalline structure. Calcite crystals tend to be tooth-like while Aragonite is long and needle like. Both are made up of Calcium Carbonate (CaCO3). The shot below also from Lechuguilla Caverns are bottlebrush formations. Bottlebrushes form when Stalagtites are in water for extended lengths of time. If the pool becomes supersaturated (much more solute which is Calcite than solvent which is water), then the Stalagtite becomes coated with Pool Spar, crystals that grow underwater, or as in the case below with mammaries. Lechuguilla Cave is the deepest cave in the United States.

A Bottlebrush formation with Pool Spar.

Ohio Caverns are located in West Liberty, Ohio. Ohio Caverns are unique because the stalagtites and stalagmites are formed by pure calcite which gives them it's white appearance. The picture below is Crystal Lake. It is a basin formed in Mammoth Cave in Kentucky. Mammoth Cave is the longest, but not the deepest cave in the world.

In Almeria, Spain a giant cave of gypsum was discovered. The cave was formed about six million years ago when the Mediterrean Sea evaporated and left these huge deposits salts that have formed into a 8 meter by 1.7 meter geode. The Spanish government is concerned about theft and has posted guards near the cave. The photos above and below can be found here.

Snotites are one of the few cave formations not developed by Calcite, Aragonite or even Carbonic Acid. According to Stephen Marshak, who wrote Essentials Of Geology, "Colonies of bacteria metabolize in sulfur-containing minerals in warm water. They create thick mats of living ooze in the complete darkness of the cave. Long gobs of this bacteria slowly drip from the ceiling" (Marshak 456). Snotites earn their name because of the mucus-like texture. The pictures above and below are snotites found in Cueva De Luz, Mexico.

Unique Cave Formations


Introduction- Spaleothems are defined as naturally occuring mineral cave depositions. The most common are stalagmites, which are columns that form from the bottom up and stalactites, which build from the top down. There are other uncommon types of spaleothems that occur such as soda straws, bacon, helictites and cave pearls. One extremely rare spaleothem formation are called anthodites. In the states of Virginia, Missouri, and Texas all of these formations are so rare that they are protected by law.

Geologic Processes- In order to understand how cave formations form, we must understand how the cavern itself is formed. Caverns are formed when either rain, runoff rain water or surface water goes into the topsoil or A-Horizon. Then Carbonic Acid and Carbon Dioxide mix with the soil when plants grow. This forms an acid that is literally cutting and eats away at the limestone to form cracks in it, much in the same way that water forces cracks to open in frost wedging. This geologic process is a type of chemical weathering.

Courtesy of

Bacon or Curtain Formations- Bacon formations are spaleothems that are thin sheets of Calcite and Iron Oxide that are deposited by water and drips from ceilings. Water is the main factor in forming bacon strips and will make a drapery formation when more and more water is left behind. These forms the orange and brown alternating bands that are make the bacon formations it's appearance. The orange and brown coloring is formed by Iron Oxide. If water continues to drop then stalagmites will form. The picture below shows a typical bacon formation.

This is a typical example of a bacon formation.

Soda Straw Formations- Soda Straws are a unique type of stalagtites that form when Carbon Dioxide gas reacts with the Calcite in caves. When this happens many rings of Calcite and form hollowlike tubes from these fragile spaleothems. If Soda Straw formations end up blocking each other during the growth of the cave, they will eventually form into a stalagtite.

Soda Straws in Carlsbad Caverns in New Mexico.

Cave-pearl formations-These formations are usually seen in younger or underdeveloped caves and caverns such as Luray and Endless Caverns in Virginia. William McGill a former state of Virginia state geologist expresses his theories on these formations. "Cave-pearls were probably formed by the crystallization of Calcium Carbonate around impurities in evaporating water. When broken they are found to be hollow and show radial structure" (McGill 133). Cave-pearls also are formed under water in shallow pools and basins. Then they are rounded by the constant rubbing against each other in water.

A formation of Cave Pearls.

Helictites are also a very interesting cave formation. These form depending on the impurities in water trickling along stalagtites and bacon formations, and end up growing like mistletoe. The factors that influence it's growth are changes in direction, humidity, temperature, and volume (McGill 121). There are many strange helictites including beet-shaped and potato-shaped ones. They also form when crystallization of calcium carbonate that have impurities or the condensation of water that does drip that also contain impurites. Below is a very unique formation of a helictite.

Anthodites are extremely rare cave formations that form in limestone caves such as Skyline Caverns in Virginia. Anthodites are named after it's Greek origin which means "flower-like" because of the thin crystal like segments growing from the base and they resemble stone flowers. Anthodites are extemely fragile and in places were they are publicly displayed, nets are placed to protect these rare formations. In the state of Missouri, a law called the "Cave Resource Act" protects the Anthodites and are protectedby the law as if were endangered species.

It is generally believed that Anthodites are formed out of a different crystalline form of Limestone (CaCO3) and is called Aragonite. Aragonite is unique because unlike Calcite which crystallizes in hexagonal (six-sided) form, Aragonite crystallizes in octahedral form, which is eight-sided.

An impressive and close-up view of Anthodites.

Products of the Geologic Process- Cavern formations produce a usual and most likely product and that is the collapse of a cave. Eventually the ceiling of caverns gets so heavy that it no longer can support the columns, stalactites, and other formations. A sinkhole is created and sediments are deposited on it or vegetation will grow upon it. Some are so deep or close to sea level that a lake will form. In some places the lake will evaporate and may form gypsum beds or playa lakes.

Impacts- The most obvious impact about cave formations is opportunity to make a quick buck here and there. Ever since these caves were first discovered tourist from around the United States have come to visit these caves and caverns such as Luray, Skyline, Ozark and Mammoth. Geologists and enviromentalists alike have pressured state governments to protect formations so that caves may continue to grow. Many states such as Texas and Virginia have already issued state laws that protect formations so that they might be available for future generations. Another impact is spaleology research. New findings are constantly being discovered. One finding is in the formation of cave coral trace amounts of opal were found in Wind Cave in South Dakota (Tullis 265). That is what makes caves so interesting.

Literature Cited









9. McGill, William. Caverns Of Virginia. State Commission on Conservation and Development. Richmond, Virginia. 1933


11. Marshak, Stephen. Essentials of Geology. New York: W. W. Norton & Company, Inc. 2004.

12. Tullis, Edward. The Black Hills Engineer. Black Hill Caves. South Dakota State School of Mines. Rapid City, South Dakota. 1938.


The Wishing Well at Luray Caverns in Virginia.

And Now For Something Truly Unique!

The Pipe Organ of Luray:

The largest musical instrument in the world is in fact in Luray Caverns. This is a very, very unique and awesome instrument that was invented in 1954 by Leland Sprinkle, an electronic scientist and mathematician at the Pentagon. Sprinkle toured many caverns in the effort to find stalagtites that would form a musical scale. The Organ is operated by electronically tipped mallets that strike the stalagtites to produce orchestral like tones. The pipe organ is three and half acres large!


Author: Jamison Brizendine
Creation/revision date: July 5, 2006

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This website was prepared as an assignment for Geosciences 211 (Physical Geology) taught in the spring of 2004 at Earlham College, Richmond, Indiana.

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