Moldavite

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Moldavite
Specific gravity
2.32 to 2.38
Optical propertiesIsotropic
Refractive index1.48 to 1.54
BirefringenceNone
PleochroismAbsent
DispersionNone
References[1]

Moldavite (

silica projectile glass formed by a meteorite impact in southern Germany (Nördlinger Ries Crater)[3] that occurred about 15 million years ago.[4] It is a type of tektite and a gemstone.[5] Material ejected from the impact crater includes moldavite, which was strewn across parts of Germany, the Czech Republic and Austria.[6]

Early studies

Moldavite was introduced to the scientific public for the first time in 1786 as "chrysolites" from

Moldau (Vltava) river in Bohemia (the Czech Republic), from where the first described pieces came.[7]

Origin

In 1900,

Nördlinger Ries crater. The impact melted material and launched it into the air. As the material was airborne, it cooled and solidified. Currently, moldavites have been found in an area that includes southern Bohemia, western Moravia, the Cheb Basin (northwest Bohemia), Lusatia (Germany), and Waldviertel (Austria).[9] Isotope analysis of samples of moldavites have shown a beryllium-10 isotope composition similar to the composition of Australasian tektites (australites) and Ivory Coast tektites (ivorites).[10]

Most moldavites are from South Bohemian localities, with just a few found in South Moravian localities. Rare moldavites have been found in the Lusatian area (near Dresden), Cheb basin area (West Bohemia) and Northern Austria (near Radessen). Principal occurrences of moldavites in Bohemia are associated with Tertiary sediments of the České Budějovice and Třeboň basins. The most prominent localities are concentrated in a NW-SE strip along the western margin of the České Budějovice Basin. The majority of these occurrences are bound to the Vrábče Member and Koroseky Sandy Gravel. Prominent localities in the Třeboň Basin are bound to gravels and sands of the Domanín Formation.

In Moravia, moldavite occurrences are restricted to an area roughly bounded by the towns of Třebíč, Znojmo and Brno. The colour of Moravian moldavites usually differs from their Bohemian counterparts, as it tends to be brownish. Taking into account the number of pieces found, Moravian localities are considerably less productive than the Bohemian ones; however, the average weight of the moldavites found is much higher. The oldest (primary) moldavite-bearing sediments lie between Slavice and Třebíč. The majority of other localities in southern Moravia are associated with sediments of Miocene as well as Pleistocene rivers that flowed across this area more or less to the southeast, similar to the present streams of Jihlava, Oslava and Jevišovka.

Properties

The chemical formula of moldavite is SiO2(+Al2O3). Its properties are similar to those of other types of glass, and reported

Mohs hardness varies from 5.5[1] to 7.[2] Moldavite can be transparent or translucent with a mossy green color, with swirls and bubbles accentuating its mossy appearance. Moldavites can be distinguished from most green glass imitations by observing their worm-like schlieren
.

Use

Moldavites were discovered by prehistoric people in the Czech Republic and Austria and were used to make flaked tools. Some of the worked moldavites date to the Aurignacian period of the Upper Paleolithic, approximately 43,000 to 26,000 years before the present.[11]

In the modern world, moldavites are often used, rough or cut, as semi-precious stones in jewelry. They have purported metaphysical qualities and are often used in crystal healing.

Presentation

There is the Moldavite Museum in Český Krumlov, Czech Republic.[12]

Gallery

  • Rough moldavite
    Rough moldavite
  • Moldavite, Czech Republic
    Moldavite, Czech Republic
  • Moldavite Czech Republic
    Moldavite Czech Republic

References

  1. ^ a b c "Moldavite". Gemdat.org. Retrieved 6 February 2016.
  2. ^ a b O'Keefe A., John. "Tektites and their Origin"., Goddard Space Centre, NASA. Retrieved 9 December 2017.
  3. ^ Artemieva, N., Pierazzo, E., Stöffler, D. (2002). "Numerical modeling of tektite origin in oblique impacts: Implication to Ries-Moldavites strewn field" (PDF). Bulletin of the Czech Geological Survey. 77. Czech Geological Survey: 303–311.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Earth Impact Database: Ries Archived 2016-03-04 at the Wayback Machine at www.passc.net/EarthImpactDatabase, Accessed 5 February 2018
  5. S2CID 234231433
    .
  6. ^ Artemieva, N., Pierazzo, E., Stöffler, D. (2002). "Numerical modeling of tektite origin in oblique impacts: Implication to Ries-Moldavites strewn field" (PDF). Bulletin of the Czech Geological Survey. 77. Czech Geological Survey: 303–311.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ "Moldavite" at Mindat.org, Accessed 5 February 2018
  8. doi:10.1016/j.gca.2008.11.003
    .
  9. ^ Trnka, M.; Houzar, S. (2002). "Moldavites: a review PDF" (PDF). Bulletin of the Czech Geological Survey. 77 (4): 283–302.
  10. doi:10.1016/j.gca.2006.12.007
    .
  11. doi:10.1016/0305-4403(77)90089-9
    .
  12. ^ "Home". Moldavite Museum. Retrieved 2022-07-08.
Wikisource has the text of the 1911 Encyclopædia Britannica article "Moldavite".

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Moldavite". Encyclopædia Britannica. Vol. 18 (11th ed.). Cambridge University Press. p. 652.

Further reading

External links

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