 | TEKTITES | Hardness | - | | Color | - | | Origin | - | | Transparency | - | | |
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| Tektites (from Greek tektos, molten) are natural glass objects up to a few centimeters in size, which most scientists argue were formed by the impact of large meteorites on Earth's surface. Tektites are typically black or olive-green, and their shape varies from rounded to irregular.
Tektites are among the "driest" rocks, with an average water content of 0.005%. This is very unusual, as most if not all of the craters where tektites may have formed were underwater before impact. Also, partially melted zircons have been discovered inside a handful of tektites. This, along with the water content, suggests that the tektites were formed under phenomenal temperature and pressure not normally found on the surface of the Earth.
Tektites are usually translucent and occur in a range of colors from green to brown. Their surfaces are usually uneven or rough, with a distinctive lumpy, jagged, or scarred texture. Tektites do not contain the crystallites found in obsidian. They may, however, have characteristic inclusions of round or torpedo-shaped bubbles or honeylike swirls. Tektites from Thailand have been carved as small, decorative objects worn in the belief that they give protection from evil.
The terrestrial-impact theory states that a meteorite impact melts material from the Earth's surface and catapults it up to several hundred kilometers away from the impact site. The molten material cools and solidifies to glass. According to this theory, a meteorite impact causes their formation, but the precursor material of tektites is primarily of terrestrial origin, as determined from isotopic measurements. Today, the terrestrial origin of tektites is widely accepted based on the results of many geochemical and isotopic studies
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