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Identification
Textites are small, hard, glassy rocks that vary in shape and may be black, clear, yellow or green. The surfaces of tektites may be smooth or marked and dented. A few types of tektites are translucent, but the majority of these stones are virtually opaque. One form of tektite, known as Moldavite, is sometimes used in jewelry.
Composition
The main component of tektites is silica. The amount of silica that an individual tektite rock contains can range from less than 70 percent to over 90 percent, varying by origin. Other elements found in tektites, in far smaller amounts, include aluminum, potassium and calcium. Unlike volcanic glasses that resemble tektites in appearance, such as obsidian, tektites do not contain water. This feature, along with the presence of lechatelierite, a type of silica glass formed under extreme heat and pressure, distinguishes tektites from other natural glasses.
Distribution
Tektites can be found in many locations around the world, but mainly in Southeast Asia, West Africa, the Caribbean and Australasia. The largest numbers of tektites have been found in Southeast Asia. Different types of tektites are named according to the location in which they are found. For example, australites come from Australia, while thailandites come from Thailand. Aboriginal Australians have used australites in rituals for thousands of years.
Formation
The shape and composition of tektite rocks indicate that tektites are formed by rock heating rapidly to a molten state and cooling again very quickly while traveling through the atmosphere at a high speed. The process results in a glass rather than crystal formation due to the rate of cooling involved. However, the cause of this process is not entirely certain.
Origins
Tektites either come from the earth or from another source outside of the earth's atmosphere. In the mid-20th century, it was generally thought that tektites came from the moon and developed their unusual shape and form while traveling through the earth's atmosphere at high speeds and striking the earth with great force. Today, however, it is thought that tektites are formed from soil and rock material on the earth when it has been thrown into the air during an impact involving great heat and pressure such as a meteorite crash. The tektites are created as the material travels into the atmosphere and back down to the earth's surface.