Moldavite is a naturally occurring glass, recognized by its distinct green hue and often intricate textures. This unique material has captivated interest due to its unusual formation process and distribution across specific regions. Unlike many geological formations, Moldavite’s existence is linked to a powerful extraterrestrial event that shaped its characteristics. It is classified as a tektite, a group of natural glasses formed under extreme conditions.
Primary Source Locations
The most significant deposits of Moldavite are found predominantly in the Czech Republic. Within this country, the primary regions include South Bohemia and Moravia, known for their Moldavite concentrations. While the majority originates from these areas, smaller quantities have also been discovered in neighboring countries like Germany and Austria. Its distribution is not uniform, with varying quantities and qualities across its known strewn fields.
Moldavite deposits in South Bohemia are particularly prominent, especially near České Budějovice, where pieces are often found in sand and clay pits. Moravian Moldavite, while less abundant, typically exhibits a slightly browner tint compared to the more vibrant green Bohemian varieties. This limited geographical occurrence contributes to Moldavite’s rarity and desirability among collectors.
The Extraterrestrial Origin Story
Moldavite’s formation began approximately 15 million years ago with a massive meteorite impact in southern Germany. This event created the Nördlinger Ries crater, measuring about 24 kilometers in diameter. The immense energy released upon impact caused terrestrial rock and sediment to melt and vaporize. This superheated, molten material was then ejected high into the atmosphere.
As the molten glass traveled through the air, it rapidly cooled and solidified before falling back to Earth. The impact propelled these molten fragments hundreds of kilometers from the site, scattering them across parts of what is now the Czech Republic, directly linking their distribution to this ancient cosmic collision in Germany.
Distinguishing Features of Moldavite
Moldavite has unique physical and chemical characteristics. Its most recognizable feature is its distinctive green color, which can range from forest green to olive green or even blue-green. The color often appears mossy, with internal swirls and bubbles.
The surface of Moldavite often displays a sculpted or etched texture, a result of its atmospheric passage and subsequent erosion by groundwater containing CO2 and humic acids. Internally, Moldavite is amorphous, lacking a crystalline structure, and is primarily composed of silicon dioxide (SiO2). It also contains trace elements and small amounts of aluminum oxide (Al2O3). A notable internal feature is the presence of worm-like inclusions called lechatelierite, which are essentially melted quartz grains formed by the intense heat of the impact.