Moldavite: Green, Glassy Meteorite Splash Glass

Write By: tmmadmin Published In: Mineral Species Created Date: 2014-12-16 Hits: 4627 Comment: 0


2" 57 carat Moldavite - Czech Republic

Moldavite is a glassy variety of tektite of cosmic origin that is a bottle-green to olive-green. It is now widely believed to have been formed by the impact of a meteorite, and is only found in the Czech Republic, primarily in southern Bohemia. It is one of a handful of gems that can claim an extraterrestrial origin. It is a popular stone with both meteorite and mineral collectors, and is also used in jewelry. It is rarely seen as gemstones, but is very popular as wire-wrapped pendants.




Closeups showing surface texture

HISTORY
Most scientists believe that moldavite was formed 15 million years ago when a giant meteorite impacted in Nördlinger Ries in southern Bavaria. Moldavite was first found along Czechoslovakia's Moldau River in 1787 by Prince Kinsky. It was described by Armand Dufrénoy the same year, and was given the name moldavite during the Jubilee Exhibition in Prague in 1891, reportedly for the town of Moldauthein in Bohemia. In 1900, based on his observations of the unique markings on the surface of moldavite, F.E.Suess published his theory that moldavites were a special class of meteorites, which he called tektites.


2.2" 75 carat Moldavite - Czech Republic


Closeup showing surface texture

SOURCES
Moldavite is found an area called the central European strewn field, which lies in the Czech Republic. This is the only area where moldavite is found. The Czech Republic has many moldavite mines, most of which are now closed. The most famous are the ones in South Bohemia, Bohemia, and Moravia, including Besednice, Locenice, Slavce, and Chlum, which produce the highest quality moldavite. Today, only four moldavite mines continue to operate in the Czech Republic. By 2020, it is estimated that current reserves will be exhausted and commercial mining of moldavite will cease. However, this prediction should probably be taken with a grain of salt, as such forecasts have been made several times since 2000.


2.2" 52 carat Moldavite - Czech Republic

MINERALOGY
Moldavite is a form of glass, with a chemical composition is about 80% SiO2, 10% Al2O3, 7% K2O, and the rest a mix of Fe, Ti, Mn, Na, Ca, and Mg. Moldavite does not crystallize, and it contains almost no water. It has a specific gravity of 2.3, a melting point of 1100ºC, and a hardness of 6.5-7.


1.8" 55 carat Moldavite - Czech Republic

PHYSICAL APPEARANCE
Moldavite is commonly found as small pieces of green glass shaped as teardrops, dumbbells, egg shapes, ellipsoids, and spheroids. Their surfaces are typically covered with deep, sharp striations resembling valleys or grooves, separated by raised ridges. The ridges on the surface can be elongated, or twisted and gnarled. They can also be covered with spiky points. Sometimes bubbles are present. These shapes are aerodynamically shaped as molten glass was splashed into the air by the impact of a colossal meteorite, imparting varying degrees of spin in one or more directions. This sculpting process is called flight ablation. Moldavite is found in a variety of colors, primarily green, and occasionally brown. The green hue ranges from dark, almost black green to mossy green to light green.


21 mm 17 carat Moldavite oval cut gemstone - Czech Republic

THEORIES OF ORIGIN
Geologists and planetary scientists have not definitively proven the exact causes of the creation of moldavite, but the meteorite impact theory is the most widely accepted.

Terrestrial source theory
This theory holds that tektites such as moldavite are made up of debris from the surface of the earth that was thrown into the air by the impact of a very large meteorite. The crash, called a hypervelocity impact, melted and vaporized the silica-rich rocks in the earth's crust, ejecting them into the air as molten material. The pieces of glass cooled and were spread over a wide area. Because strewn fields are scarce, it is believed that very special and rarely occurring circumstances are required for the formation of tektites. Some believe that for tektites to form, the meteorite must be super-heated and must hit at a very low angle.


1.6" 70 carat Moldavite - Czech Republic

Non-terrestrial source theories
Another theory holds that parts of the meteorite itself were melted and sprayed out by the impact, and that this material became tektites. Other theories for the source of tektites include the impact of a meteorite on the moon, which sprayed the earth with tektites; and that lunar volcanoes scattered material into space, which later fell on the earth. There is much contradictory evidence in support of the various theories, and the only thing certain is that no one knows for sure exactly how moldavite was created.


1.8" 73 carat Moldavite - Czech Republic

SUMMARY
Moldavite will most likely continue to rise in price, particularly if any of the remaining mines close in the near future. For now, there is a good supply of good quality material available at reasonable prices, and this will no doubt continue as long as the supply pipeline remains full.


2.1" 71 carat Moldavite - Czech Republic

All photos by www.TreasureMountainMining.com

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