Crystal Grottoes
Encyclopedia
Crystal Grottoes is the only show cave
in the U.S.
state
of Maryland
. It is located on Maryland Route 34
between Boonsboro
and Antietam National Battlefield
.
A fire in December 2007 caused substantial damage to the visitors center.
cave
, formed in a anticline
in a bed of Tomstown Dolomite
. The cave is essentially horizontal throughout its extent and the passages are typically high and narrow. A great deal of brown and red clay fills most of the cave to a considerable extent; the commercial tour routes involved the removal of up to 6 feet (1.8 m) of this clay in places. Sediment fills many of the undeveloped passages to within a foot or two of the ceiling, thereby making many crawlways. No streams exist in the cave, although a small "lake" or pool is maintained by drip water.
Most of the rooms abound in formation
s, generally stalactite
s, flowstone
, and columns. They are typically white or buff, with one area (called Fairyland) tinted a light blue, perhaps by copper oxides.
The first room is 8 feet (2.4 m) below the entrance house and is oblate in shape, being 30 feet (9.1 m) long, 10 feet (3 m) wide, and 15 feet (4.6 m) high. At each end it is pinched out by mud flows and narrowing of the passage. This room originally contained a considerable number of formations, but quarrying operations and clearing of passages have removed them except along the west wall where flowstone and stalactites are abundant.
With the exception of the passage from the Blanket Room to the exit, the passages are continuously lined or covered by formations. Delicate drape-like stalactites, bacon rinds, and stout columns predominate. The colors are generally pure white or buff with occasional deeper tints. The passages forming Fairyland are studded with stalactites and stalagmites of a delicate light blue hue.
The Blanket Room is the largest room in the caverns at 30 feet (9.1 m) and 20 feet (6.1 m) wide. Large sheets of stalactites and bacon rind hang in clusters from the ceiling, which is here 20 feet (6.1 m) high.
The passage leading to the Golden Lake is profuse with formations and in part is bridged by flat-lying travertine, a condition that is found in many of the passages not open to the public. The Golden Lake is a small pool fed by water dripping from the ceiling. In wet seasons the water accumulates at a rate necessitating periodic bailing.
The passages not open to the public are similar to those already described except they are constricted at many points. Orange-brown clay that covers the floor and lower walls of these passages is often overlain by calcareous formations. The commercial tour route covers approximately one third of the known cave.
Unlike many show caves, the electric lighting at Crystal Grottoes is uncolored, allowing the visitor to see the formations' natural appearance.
Show cave
Show caves — also called tourist caves, public caves, and in the United States, commercial caves — are caves that are managed by a government or commercial organization and made accessible to the general public, usually for an entrance fee...
in the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
. It is located on Maryland Route 34
Maryland Route 34
Maryland Route 34 is a state highway in the U.S. state of Maryland. Known for most of its length as Shepherdstown Pike, the state highway begins at the West Virginia state line at the Potomac River, where the highway continues south as West Virginia Route 480 through Shepherdstown. The state...
between Boonsboro
Boonsboro, Maryland
Boonsboro is a town in Washington County, Maryland, United States, located at the foot of South Mountain. It nearly borders Frederick County and is proximate to the Antietam National Battlefield...
and Antietam National Battlefield
Antietam National Battlefield
Antietam National Battlefield is a National Park Service protected area along Antietam Creek in Sharpsburg, Maryland which commemorates the American Civil War Battle of Antietam that occurred on September 17, 1862...
.
History
Crystal Grottoes was discovered in 1920 in the course of quarrying operations by a road construction crew trying to obtain gravel. A drill bit (for placing explosives) disappeared into a hole, and the crew realized they had found a cave. Blasting produced the entrance which is still used, and in 1922 the cave was opened to the public. A mapping operation in 1968 revealed about a half mile of passages, but only about one third of the cave is accessed during the tour, which takes about forty minutes.A fire in December 2007 caused substantial damage to the visitors center.
Geology
Crystal Grottoes is an example of a karstKARST
Kilometer-square Area Radio Synthesis Telescope is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors on karst landforms, which are bowlshaped limestone sinkholes named after the Kras region in Slovenia and Northern Italy. It will consist of...
cave
Cave
A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...
, formed in a anticline
Anticline
In structural geology, an anticline is a fold that is convex up and has its oldest beds at its core. The term is not to be confused with antiform, which is a purely descriptive term for any fold that is convex up. Therefore if age relationships In structural geology, an anticline is a fold that is...
in a bed of Tomstown Dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
. The cave is essentially horizontal throughout its extent and the passages are typically high and narrow. A great deal of brown and red clay fills most of the cave to a considerable extent; the commercial tour routes involved the removal of up to 6 feet (1.8 m) of this clay in places. Sediment fills many of the undeveloped passages to within a foot or two of the ceiling, thereby making many crawlways. No streams exist in the cave, although a small "lake" or pool is maintained by drip water.
Most of the rooms abound in formation
Speleothem
A speleothem , commonly known as a cave formation, is a secondary mineral deposit formed in a cave. Speleothems are typically formed in limestone or dolostone solutional caves.-Origin and composition:...
s, generally stalactite
Stalactite
A stalactite , "to drip", and meaning "that which drips") is a type of speleothem that hangs from the ceiling of limestone caves. It is a type of dripstone...
s, flowstone
Flowstone
Flowstones are composed of sheetlike deposits of calcite formed where water flows down the walls or along the floors of a cave. They are typically found in "solution", or limestone caves, where they are the most common speleothem. However, they may form in any type of cave where water enters that...
, and columns. They are typically white or buff, with one area (called Fairyland) tinted a light blue, perhaps by copper oxides.
The first room is 8 feet (2.4 m) below the entrance house and is oblate in shape, being 30 feet (9.1 m) long, 10 feet (3 m) wide, and 15 feet (4.6 m) high. At each end it is pinched out by mud flows and narrowing of the passage. This room originally contained a considerable number of formations, but quarrying operations and clearing of passages have removed them except along the west wall where flowstone and stalactites are abundant.
With the exception of the passage from the Blanket Room to the exit, the passages are continuously lined or covered by formations. Delicate drape-like stalactites, bacon rinds, and stout columns predominate. The colors are generally pure white or buff with occasional deeper tints. The passages forming Fairyland are studded with stalactites and stalagmites of a delicate light blue hue.
The Blanket Room is the largest room in the caverns at 30 feet (9.1 m) and 20 feet (6.1 m) wide. Large sheets of stalactites and bacon rind hang in clusters from the ceiling, which is here 20 feet (6.1 m) high.
The passage leading to the Golden Lake is profuse with formations and in part is bridged by flat-lying travertine, a condition that is found in many of the passages not open to the public. The Golden Lake is a small pool fed by water dripping from the ceiling. In wet seasons the water accumulates at a rate necessitating periodic bailing.
The passages not open to the public are similar to those already described except they are constricted at many points. Orange-brown clay that covers the floor and lower walls of these passages is often overlain by calcareous formations. The commercial tour route covers approximately one third of the known cave.
Unlike many show caves, the electric lighting at Crystal Grottoes is uncolored, allowing the visitor to see the formations' natural appearance.