|Dimensions (mm)||22 x 18 x 9mm|
|Weight (carats)||15.03 carats|
This is a natural untreated specimen hand selected from a large parcel from a collector for it unique structure and quality.
It is app 14 million years old and it is from the Moldau valley in the Czeh republic.
Great piece for a collection.
Tektites (from Greek tektos, molten) are natural glass rocks up to a few centimeters in size, which most scientists argue were formed by the impact of large meteorites on Earth's surface. Tektites are typically black or olive-green, and their shape varies from rounded to irregular.
The ages of tektites from the four strewnfields have been determined using radiometric dating methods. The age of moldavites, a type of tektite found in Czech Republic, was determined to be 14 million years, which agrees well with the age determined for the Nördlinger Ries crater (a few hundred kilometers away in Germany) by radiometric dating of Suevite (an impact breccia found at the crater). Similar agreements exist between tektites from the North American strewnfield and the Chesapeake Bay impact crater and between tektites from the Ivory Coast strewnfield and the Lake Bosumtwi-Crater.
Early non-terrestrial impact theories
Though the meteorite impact theory of tektite formation is widely accepted, minority theories propose alternate ideas of tektite formation.
Tektites contain no cosmogenic noble gases produced by cosmic rays, a factor that excludes long travel in space, necessary if tektites are not terrestrial. According to terrestrial-impact adherents, this makes a lunar origin unlikely, because it is hard to reconcile with finding cosmogenic noble gases in all lunar meteorites – a typical lunar meteorite taking about 1 million years to transfer from Moon to Earth. Furthermore, an origin from the Moon or other body cannot explain why many tektites are only found in confined areas unlike meteorites of lunar or other origin, which are found dispersed on the Earth's surface. Whether the Australasian and Ivory Coast tektites fit this thesis is debatable.
In particular, no tektite strewn field exists in Antarctica, where the flow of glaciers would sweep extraterrestrial material away. Since the Australasian strewnfield expands with each new tektite discovered on the southern seafloor, this tektite field may yet be found to reach as far as Antarctica, but regularly undertaken meteorite recovery expeditions in areas that accumulate extraterrestrial material have found only meteorites and no tektites at all. If tektites from space fall in Antarctica, a large part of the recovered material should instead be tektites and an existing strewnfield should already have been discovered. Conversely, the Australasian and Ivory Coast strewnfields have expanded over the decades as new tektites are found in sea sediments; they now reach toward the southern continent. Thus, it may be premature for terrestrial-origin proponents to say that tektites will never be discovered on Antarctica.
|Starts||13th Feb 2020 2:46pm PST|
|Ends||14th Feb 2020 2:46pm PST|
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