Natural, silica-rich glasses produced by melting of target rocks and dispersal as droplets during terrestrial impact events. In contrast to most impact glasses, which are found inside or within the immediate vicinity of impact structures, tektites are distal impact ejecta. They range in color from black or dark brown to type whose name is derived from the Moldau (Vltava) river in the Czech Republic where the first pieces were identified. The vast majority of moldavites originate from the Czech Republic where they are mined. Moldavites are generally translucent with extensive etching, and forest green to olive green in color. However, there can be a wide range of opacity, texture and color. For example Moravian moldavites are opaque and dark brown, Lusatian moldavites are smooth, translucent and bright green, and moldavites from Brusna are a pale green with a white frosted and deeply etched appearance.
Moldavites formed about 14.808 ± 0.038 million years ago (middle Miocene epoch) when what is hypothesized to be a binary asteroid impacted the sand-rich surface layer of what is now Germany with such force that the larger 1.5 km wide mass formed the ~24 km Nördlinger Ries rampart Bowl-like depression ("crater" means "cup" in Latin) on the surface of a planet, moon, or asteroid. Craters range in size from a few centimeters to over 1,000 km across, and are mostly caused by impact or by volcanic activity, though some are due to cryovolcanism. and the smaller 0.15 km mass created the 3.8 km diameter Steinheim crater. The molten Fractured and/or molten rocky debris thrown out of a crater during a meteorite impact event, or, alternatively, material, including ash, lapilli, and bombs, erupted from a volcano. from the Nördlinger Ries impact cooled as it flew as far as ~450 km from the crater. As the tektites were subsequently covered in soil, water and/or gravel over the millions of years, then underwent various types of etching and Removal of weathered rocks by moving water, wind, or ice. processes often unique to the area where they landed thus leading to the delicately figured and deeply etched Besenice moldavites in one type of soil and the rounded and smooth Lusatian moldavites found in gravel pits in Germany. Moldavites have purported to be found in Austria and Poland. The figuring and etching of moldavites is diagnostic of their Meteorite not seen to fall, but recovered at some later date. For example, many finds from Antarctica fell 10,000 to 700,000 years ago. location and moldavite experts can identify their location strictly by visual clues.
Moldavites can be distinguished from fakes created using green bottle glass and often peddled on eBay by observing their trapped air bubbles and worm-like inclusions of An amorphous silica glass formed naturally by the heat of impact/detonation of a large meteorite on/over quartz sand. Lechatelierite is found as an inclusion in Libyan Desert Glass. Most commonly formed during lightning strikes in sand. Named for Henry Louis Le Chatelier (1850-1936), a French chemist.. Moldavites are NEVER red, light blue or yellow. Fakes are cast glass and do not have the sharp etching most often found in real moldavites.