Moonmilk

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Moonmilk
Mondmilch, Montmilch, Cave milk
Speleothem rock
Bergmilchkammer 04.jpg
Moonmilk ostensibly created from Macromonas bipunctata in the cave Bergmilchkammer
Composition
Carbonates (e.g., calcite, aragonite, hydromagnesite, monohydrocalcite)
TextureCreamy, soft
Diagram of dripstone cave structures (moonmilk is labelled I) Tropfsteine.svg
Diagram of dripstone cave structures (moonmilk is labelled I)

Moonmilk (sometimes called mondmilch, also known as montmilch or cave milk) is a white, creamy substance found inside limestone, dolomite, and possibly other types of caves. It is a precipitate from limestone comprising aggregates of fine crystals of varying composition, usually made of carbonates such as calcite, aragonite, hydromagnesite, and/or monohydrocalcite.

Contents

Formation and Composition

Moonmilk forms as a result of several processes, including both chemical reactions and possible bacterial action. One hypothesis suggests that moonmilk is created by the bacterium Macromonas bipunctata . However, no microbiological studies have been carried out to confirm this. Moonmilk was originally thought to be created by moon rays, a misconception reflected in its name. [1]

It is possible that moonmilk forms when water dissolves and softens the karst in caves, carrying dissolved nutrients that are used by microbes, such as Actinomycetes. As microbial colonies grow, they trap and accumulate chemically precipitated crystals in an organic matter-rich matrix. These heterotrophic microbes, which produce CO2 as a waste product of respiration and possibly organic acids, may help to dissolve the carbonate.[ citation needed ]

Historical and Cultural Uses

In 2017, archaeologists at the University of Chinese Academy of Sciences in China discovered a bronze jar dating back over 2,700 years, containing animal fat combined with moonmilk. This mixture is believed to have been used as a cosmetic face cream by Chinese noblemen. [2]

Being soft, moonmilk was frequently used as a medium for finger fluting, a form of prehistoric art.

The Swiss naturalist Conrad Gessner described moonmilk's use as a medicine in the 16th century. It continued to be prescribed until the 19th century. [3]

Notable Formations

The world's largest formation of brushite moonmilk is found in the Big Room of Kartchner Caverns State Park in southern Arizona. [4]

Related Research Articles

<span class="mw-page-title-main">Cave</span> Natural void under the Earths surface

A cave or cavern is a natural void under the Earth's surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance underground. Caves which extend further underground than the opening is wide are called endogene caves.

<span class="mw-page-title-main">Limestone</span> Type of sedimentary rock

Limestone is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of CaCO3. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life.

<span class="mw-page-title-main">Stalactite</span> Elongated mineral formation hanging down from a cave ceiling

A stalactite is a mineral formation that hangs from the ceiling of caves, hot springs, or man-made structures such as bridges and mines. Any material that is soluble and that can be deposited as a colloid, or is in suspension, or is capable of being melted, may form a stalactite. Stalactites may be composed of lava, minerals, mud, peat, pitch, sand, sinter, and amberat. A stalactite is not necessarily a speleothem, though speleothems are the most common form of stalactite because of the abundance of limestone caves.

<span class="mw-page-title-main">Calcite</span> Calcium carbonate mineral

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses.

<span class="mw-page-title-main">Calcium carbonate</span> Chemical compound

Calcium carbonate is a chemical compound with the chemical formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls. Materials containing much calcium carbonate or resembling it are described as calcareous. Calcium carbonate is the active ingredient in agricultural lime and is produced when calcium ions in hard water react with carbonate ions to form limescale. It has medical use as a calcium supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues.

<span class="mw-page-title-main">Sodium carbonate</span> Chemical compound

Sodium carbonate is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils, and because the ashes of these sodium-rich plants were noticeably different from ashes of wood, sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process, as well as by carbonating sodium hydroxide which is made using the Chlor-alkali process.

<span class="mw-page-title-main">Stalagmite</span> Elongate mineral formation found on a cave floor

A stalagmite is a type of rock formation that rises from the floor of a cave due to the accumulation of material deposited on the floor from ceiling drippings. Stalagmites are typically composed of calcium carbonate, but may consist of lava, mud, peat, pitch, sand, sinter, and amberat.

<span class="mw-page-title-main">Travertine</span> Form of limestone deposited by mineral springs

Travertine is a form of terrestrial limestone deposited around mineral springs, especially hot springs. It often has a fibrous or concentric appearance and exists in white, tan, cream-colored, and rusty varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites, stalagmites, and other speleothems. It is frequently used in Italy and elsewhere as a building material. Similar deposits formed from ambient-temperature water are known as tufa.

<span class="mw-page-title-main">Speleothem</span> Structure formed in a cave by the deposition of minerals from water

A speleothem is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending on their depositional history and environment. Their chemical composition, gradual growth, and preservation in caves make them useful paleoclimatic proxies.

<span class="mw-page-title-main">Luray Caverns</span> Cave in Virginia, United States

Luray Caverns, previously Luray Cave, is a cave just west of Luray, Virginia, United States, which has drawn many visitors since its discovery in 1878. The cavern system is adorned with speleothems such as columns, mud flows, stalactites, stalagmites, flowstone, and mirrored pools. The caverns host the Great Stalacpipe Organ, a lithophone made from solenoid-fired strikers that tap stalactites of varied sizes to produce tones similar to those of xylophones, tuning forks, or bells.

<span class="mw-page-title-main">Moonlight</span> Light that reaches Earth from the Moon

Moonlight consists of mostly sunlight reflected from the parts of the Moon's surface where the Sun's light strikes.

<span class="mw-page-title-main">Dolomite (rock)</span> Sedimentary carbonate rock that contains a high percentage of the mineral dolomite

Dolomite (also known as dolomite rock, dolostone or dolomitic rock) is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO3)2. It occurs widely, often in association with limestone and evaporites, though it is less abundant than limestone and rare in Cenozoic rock beds (beds less than about 66 million years in age). One of the first geologists to distinguish dolomite from limestone was Déodat Gratet de Dolomieu; a French mineralogist and geologist whom it is named after. He recognized and described the distinct characteristics of dolomite in the late 18th century, differentiating it from limestone.

<span class="mw-page-title-main">Sugar candy</span> Candy primarily composed of sugar

Sugar candy is any candy whose primary ingredient is sugar. The main types of sugar candies are hard candies, fondants, caramels, jellies, and nougats. In British English, this broad category of sugar candies is called sweets, and the name candy or sugar-candy is used only for hard candies that are nearly solid sugar.

<span class="mw-page-title-main">Treak Cliff Cavern</span> Show cave in Derbyshire, England

Treak Cliff Cavern is a show cave near Castleton in Derbyshire, England. It is part of the Castleton Site of Special Scientific Interest and one of only two sites where the ornamental mineral Blue John is still excavated. As part of an agreement with English Nature, the Blue John that can be seen in the show cave is not mined but it is extracted in small quantities from other areas of the cave and made into saleable items like bowls, jewellery, and ornaments.

<span class="mw-page-title-main">Carlsbad Caverns National Park</span> National Park in New Mexico, United States

Carlsbad Caverns National Park is an American national park in the Guadalupe Mountains of southeastern New Mexico. The primary attraction of the park is the show cave Carlsbad Cavern. Visitors to the cave can hike in on their own via the natural entrance or take an elevator from the visitor center.

<span class="mw-page-title-main">Calcite rafts</span> Cave-crystallized calcite crusts

Calcite crystals form on the surface of quiescent bodies of water, even when the bulk water is not supersaturated with respect to calcium carbonate. The crystals grow, attach to one other and appear to be floating rafts of a white, opaque material. The floating materials have been referred to as calcite rafts or "leopard spots".

<span class="mw-page-title-main">Indiana Caverns</span>

Indiana Caverns is part of the Binkley Cave system near Corydon, Indiana.

<i>Macromonas bipunctata</i> Species of bacterium

Macromonasbipunctata is a Gram-negative, colorless, and heterotrophic sulfur bacterium of the genus Macromonas. It is commonly found in sewage aeration tanks and caves where moonmilk has formed. In the 1920s, researcher Gicklhorn first discovered this organism under the name Pseudomonasbipunctata. After further study and culturing by Utermöhl and Koppe, in 1923, it was later renamed Macromonasbipunctata. This organism is thought to be non-pathogenic species. In fact, the moonmilk produced was referenced as a remedy for infections in the Middle Ages.

<span class="mw-page-title-main">Hells Bells (cave formations)</span> Underwater cave formation

Hells Bells are hollow bell- or cone-shaped structures of carbonate that can reach lengths of 2 metres. They are found underwater in El Zapote cenote in Quintana Roo, Mexico, on the Yucatan Peninsula; similar formations exist in other caves. In a certain depth range, such structures cover the entire surface of the cave including submerged tree trunks and other Hells Bells, although they never touch each other.

<span class="mw-page-title-main">Silicification</span> Geological petrification process

In geology, silicification is a petrification process in which silica-rich fluids seep into the voids of Earth materials, e.g., rocks, wood, bones, shells, and replace the original materials with silica (SiO2). Silica is a naturally existing and abundant compound found in organic and inorganic materials, including Earth's crust and mantle. There are a variety of silicification mechanisms. In silicification of wood, silica permeates into and occupies cracks and voids in wood such as vessels and cell walls. The original organic matter is retained throughout the process and will gradually decay through time. In the silicification of carbonates, silica replaces carbonates by the same volume. Replacement is accomplished through the dissolution of original rock minerals and the precipitation of silica. This leads to a removal of original materials out of the system. Depending on the structures and composition of the original rock, silica might replace only specific mineral components of the rock. Silicic acid (H4SiO4) in the silica-enriched fluids forms lenticular, nodular, fibrous, or aggregated quartz, opal, or chalcedony that grows within the rock. Silicification happens when rocks or organic materials are in contact with silica-rich surface water, buried under sediments and susceptible to groundwater flow, or buried under volcanic ashes. Silicification is often associated with hydrothermal processes. Temperature for silicification ranges in various conditions: in burial or surface water conditions, temperature for silicification can be around 25°−50°; whereas temperatures for siliceous fluid inclusions can be up to 150°−190°. Silicification could occur during a syn-depositional or a post-depositional stage, commonly along layers marking changes in sedimentation such as unconformities or bedding planes.

References

  1. Gessner, Conrad (1555). Descriptio Montis Fracti sive Montis Pilati [Description of Mount Fractus, or Mount Pilatus] (in Latin). p. 54. Retrieved March 12, 2016.
  2. Marshall, Michael (2019-02-26). "2700-year-old face cream was made from animal fat and cave 'milk'". New Scientist. Retrieved 2021-02-08.
  3. Moonmilk Archived 2012-05-31 at the Wayback Machine in showcaves.com.
  4. Cronkite, Amy. "State celebrates 10 years of Kartchner Caverns Big Room tours" . Retrieved 27 February 2015.