Grand Caverns Formations

Cave Coral/Popcorn

As calcium settled and crystallized in pools of water throughout the cave it formed what is known as cave coral or popcorn. This was formed much the same way that rock candy is made. This forms in small, sharp formations measuring approximately 1/8 inch long and very close to each other, resembling the coral found in oceans.

 Colors of the Cave

White is (calcite/calcium carbonate) is the basic mineral in most formations. As rain soaks though the ground it dissolves the calcite from limestone. Pure calcite is white and impurities add color.

Red (iron/iron oxide) is caused when water containing iron minerals coats the outer layers of formations giving them a reddish color. The inside of the formations are still white form the calcite.)

Grey (limestone) is found throughout the cave.

Grey (manganese) is rare and not much is found in Grand Caverns.

Green (cave algae) is NOT a mineral but a green growth caused by dampness mixed with heat, lint form clothing and light from light bulbs.

  Dog Tooth Spar

Dogtooth spar consists of very large calcite crystals that resemble dog’s teeth. These are usually found near water and most of the time are found in caves which have or have had seasonal flooding.

Draperies

Draperies are formed when water flows evenly down just one side of a stalactite. Because water zigzags as it flows downward, these formations develop tiny folds looking much like draperies.

Flowstone

Flowstone is formed by the continuous deposit of calcite from water flowing over a surface. Flowstone is a smooth waterfall like formation and can cover mounds of clay, coat limestone walls, and ooze over passageways. Most of the walls and floors of Grand Caverns are covered with flowstone.

  Shields

Shields are disc like projections from the walls, ceiling, and floors of the cave. It is not known how shields are formed but one theory requires that pressurized water shooting out of a thin crack. Shields are formed of two thin disks separated by a thin space where water circulates. It is believed that the vertical orientation of the limestone in Grand Caverns may contribute to the abundance of these relatively rare formations. Hundreds of shield formations can be found throughout Grand Caverns.

 Soda Straws

Soda straws grow from the ceiling. They are thin walled, hollow tubes in which the water runs inside of them and deposits rings of calcite around their tips. Eventually these will overgrow and become stalactites.

Stalactites

A formation which hangs from the ceiling or forms by growing down is known as a stalactite As water droplets fall from the ceiling, a small amount of calcite is deposited in the form of a small ring. Each ring forms on the previous so that they stack up. The young stalactites are known as soda straws and are hollow as long as water flows through their center. Most stalactites are long and thin with pointed ends. As water flows down the outside, this leaves a thin layer that eventually forms a conical shape.

Stalagmites

Stalagmites are formed by water dropping from above and depositing minerals. As the water drops and spreads out before it evaporates, the base of a stalagmite is solid, not hollow like soda straw formations. The base of stalagmites may resemble a fried egg and are sometimes fat and thick with rounded tops. Stalagmites reach up from the floor.

Water Lines

Water lines are created when water stands in one place for a long period of time. The deposits form at the rim of the top of the water leaving water lines as the water dissipates.

The information contained on this page is for general purposes only and may not contain the most current information. For answers to more specific questions or concerns, or to receive the latest information possible, please call the Grand Caverns main office.