Large Black Indochinite Tektite Stone

Weight:  42.9 gram

Size:  59x30x22 mm  
 

Location: Sourced at Zhanjiang city, Guangdong Province, S. China

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Tektite

Tektites are gravel-size bodies that are composed of black, green, brown or gray, natural glass that are formed from terrestrial debris ejected during extraterrestrial impacts. They are characterized by 1. a fairly homogeneous composition; 2. an extremely low content of water and other volatiles; 3. an abundant lechatelierite; 4. a general lack of microscopic crystals known as microlites and chemical relation to the local bedrock or local sediments; and 5. their distribution within geographically extensive strewnfields. Tektites generally range in size from centimeters to millimeters. Millimeters-size tektites are known as microtektites.

Although tektites are superficially similar to some terrestrial volcanic glasses (obsidians), they have unusual distinctive physical characteristics that distinguish them from such glasses. First, they are completely glassy and lack any microlites or phenocrysts unlike terrestrial volcanic glasses. Second, although high in silica (>65 wt%), the bulk chemical and isotopic composition of tektites is closer to those of shales and similar sedimentary rocks and quite different from the bulk chemical and isotopic composition of terrestrial volcanic glasses. Third, tektites contain virtually no water (<0.02 wt%) unlike terrestrial volcanic glasses. Fourth, the flow-banding within tektites often contains particles and bands of lechatelierite, which are not found in terrestrial volcanic glasses. Finally, a few tektites contain partly melted inclusions of shocked and unshocked mineral grains, i.e. quartz, apatite, and zircon, as well as coesite.

The difference in water content can be used to distinguish tektites from terrestrial volcanic glasses. When heated to their melting point, terrestrial volcanic glasses will turn into a foamy glass because of their content of water and other volatiles. Unlike terrestrial volcanic glass, a tektite will produce only a few bubbles at most when heated to its melting point because of its much lower water and other volatiles content.

Indochinites (South East Asia, dark, mostly black)

Indochinite Tektites are solidified rock, which were fired into the Earth's upper atmosphere by a meteorite impact and subsequently cooled to form the distinctive glass-like structure. Indochinite Tektites are distinctly dark black in contrast to the green of European Moldavite Tektites. It is estimated that these bodies of solidified magma are 700,000 years old. Indochinite tektites, as the name suggests, are found in the Indochinese peninsula, from Australia and the Pacific islands of Micronesia in the east and south, to China and Indonesia in the north and west. The largest indochinite was a Muong-Nong type tektite (which are layered tektites), which had a mass of 29.0 kg.