Tektite China Hainan (4) Meteorites Raw Minerals Stones Rocks Collecting

Fragment of Tektite Indocinite of meteoric origin 7 gr - mm 28 x 17 x 10 Meteorites Raw Minerals Stones Rocks for Collection, in plexiglas box with white bottom cm 4.2 x 3.7 x 3.2 h, only a piece, as in photos.
This species from China, ever black in color, has been polished for decorative purposes.
Included to the Meteorite a geological tab dates paper.

The Tektites (from the Greek tektos, fused) are natural glass objects, found on the Earth's surface, consisting mainly of silicates that, according to most scientists, were formed as a result of the impact of large meteorites. Tektites are among the most anhydrous rocks, with an average water content of 0.005%, which suggests that the tektites were formed under conditions of very high temperatures and pressures not normally present on the planet's surface.
The size of the tektites varies from a few millimeters to a few centimeters. The smallest, with millimetric dimensions, are known as microtektites.
The Earth impact theory states that a meteoric impact has melted the Earth's crust and catapulted part of these rocks fused to many hundreds of kilometers away from the impact site. The melted materials are then precipitated and cooled assuming various forms of glass structure. According to this theory, although a meteorite has caused its fusion, the material of which the tectites are constituted is primarily of terrestrial origin, as determined by isotopic measurements. The color of the tektites is black or olive green, and their shape varies from roundish to irregular.
According to the impact theory, tektites can not be found anywhere on the earth's surface, but only in narrow areas, called dispersion areas, three of which are associated with known impact craters. Only the most extensive and geologically young deposits of tektites in Southeast Asia, called the Australasian dispersal area, have no impact crater associated with them. This is probably due to the fact that any large impact structure is often difficult to detect. For example, due to the impact crater sedimentary cover. In addition, the larger the area of ​​the fall, the greater the area in which the crater is to be searched. Since many new craters are identified each year, this is not considered a problem by those supporting the Earth impact theory, with the exclusion of the expected Australoasian crater, a structure that should be no more than one million years old and therefore easily visible. This crater, if it exists, has not yet been localized. Another hypothesis connects these tektites to the crater of the Earth of Wilkes in Antarctica, formed following an impact that occurred about 250 million years ago that would have erased 90% of life on Earth and has been linked to the great species extinction living at the end of the Permian period.
The tektites are named according to the area of ​​discovery: Australians (dark, often black) those found in Australia, Indochinites (dark, often black) those found in Thailand, Vietnam, Laos and Cambodia, Cinesites (black) those found in China, and so on.
The ages of the tektites, coming from four main planetary areas, were determined using the radiometric dating method. The age of moldavites, eg, a type of tektite found in the Czech Republic, was set at 14 million years ago, which is consistent with the age set for the Ries Crater in Nördlingen, Germany, through the radiometric dating of suevite (a breach of impact found in the crater).