Come nei tanti film di fantascienza, quando una improvvisa pioggia di meteoriti minaccia il nostro pianeta con il pericolo estinzione. E dire che fantasia non lo è stata qui, perché i meteoriti in questo luogo sono caduti sul serio. Quello di Nördlingen, in tedesco Nördlinger Ries, è uno dei crateri meteorici più conosciuti del mondo. E non ha minacciato grattacieli né civiltà perdute: è caduto dal cielo circa 15 milioni di anni fa, quando ancora di civiltà e specie animali non vi era traccia. O quasi. Read more (Italian)
Moldavite - Tektite from Locenice Moldau River Valley, Czech Republic
Tektite is a silicate glass formation, the origin of which was long considered a mystery. The name comes from the Greek tektos, meaning melted, and it is now agreed that tektites are formed when a meteorite slams into the Earth. The immense heat and pressure of the impact liquefies terrestrial rocks, splashing them into the upper atmosphere; these liquid rock droplets then return to Earth as solidified glass. Moldavite is named for the river valley in which it was first found in the Czech Republic, a result of the asteroid impact that created the 14.5 mile diameter Nördlinger-Reis crater near Stuttgart in Germany almost 15 million years ago. Moldavite is prized for its clarity, shape and green colour, all of which this specimen displays beautifully; light passing through the specimen reveals its lovely green colour, the clarity indicating a high silica content (in moldavite, typically 80%). Pieces of moldavite were valued as talismanic objects in Palaeolithic times, worn as pendants in the Middle Ages, and in the 17th-19th centuries it was often offered by men to their fiancées as a charm to assure harmony in their forthcoming marital relations. Moldavite is found in two grades, regular and museum. This piece shows the pale translucence and fine fern-like patterning and texture of the latter; an exquisite example, this specimen measures approximately 1 5/8 x 1 5/8 x ¾ inches and weighs 28.35 grams.
Yesterday, I accidentally walked into a crystal shop in Glendale. I stumbled upon a very curious stone called Moldavite. Its is a translucent green meteoric gem, found only in what is now the Czech Republic. Classed with the mysterious group of glassy objects called tektites, it is believed to have fallen from the sky only once, about 14.8 million years ago. Read more
A rough-textured pine-green natural glass, moldavite resembles nothing so much as the mythical Kryptonite. It is a kind of tektite, formed by the heat wave of a meteorite striking earth, then cooled as terrestrial material hurtles through the atmosphere to land dozens or hundreds of miles away. Moldavites, specifically, are tektites created when a meteor crashed into what is now western Bavaria 14 million years ago. Most often found in Bohemia in the Czech Republic, they have been used there as a local gemstone for centuries.
About 14.7 million years ago, in the Miocene, a impact crater was caused by a meteorite at a place what is now known as Nordlingen Ries, Germany and at Steinheimer, Germany. The depression has a circular shape and is 25 km in diameter. The bottom of the crater is about 100-150 m below the brink. The city of Nördlingen is located in the middle of the crater. The impact craters are filled with suevite breccias, shattercones, and impact melts. This impact that also created the gem green moldavite tektites. The word "Ries" is not a German word; it is believed that the term is derived from the name of a tribe, Raetians, who lived in the area in pre-Roman times.