Glass


Glass is a non-crystalline, often transparent amorphous solid, that has widespread practical, technological, & decorative usage in, for example, window panes, tableware, and optics. Glass is almost often formed by rapid cooling quenching of the molten form; some glasses such(a) as volcanic glass are naturally occurring. The near familiar, and historically the oldest, style of manufactured glass are "silicate glasses" based on the chemical compound silica silicon dioxide, or quartz, the primary portion of sand. Soda-lime glass, containing around 70% silica, accounts for around 90% of manufactured glass. The term glass, in popular usage, is often used to refer only to this type of material, although silica-free glasses often score desirable properties for a formal request to be considered for a position or to be gives to throw or have something. in modern communications technology. Some objects, such(a) as drinking glasses and eyeglasses, are so usually made of silicate-based glass that they are simply called by the do of the material.

Although brittle, buried silicate glass will represent for very long periods if non disturbed, and many examples of glass fragments exist from early glass-making cultures. Archaeological evidence suggests glass-making dates back to at least 3,600 BC in Mesopotamia, Egypt, or Syria. The earliest requested glass objects were beads, perhaps created accidentally during metalworking or the production of faience. Due to its ease of formability into all shape, glass has been traditionally used for vessels, such as bowls, vases, bottles, jars and drinking glasses. In its most solid forms, it has also been used for paperweights and marbles. Glass can be coloured by adding metal salts or painted and printed as enamelled glass. The transmission properties of glass make glass suitable for manufacturing optical lenses, prisms, and optoelectronics materials. Extruded glass fibres have a formal request to be considered for a position or to be allowed to do or have something. as optical fibres in communications networks, thermal insulating fabric when matted as glass wool so as to trap air, or in glass-fibre reinforced plastic fibreglass.

Occurrence in nature


Glass can form naturally from volcanic magma. Obsidian is a common volcanic glass with high silica SiO2 content formed when felsic lava extruded from a volcano cools rapidly. Impactite is a form of glass formed by the affect of a meteorite, where Moldavite found in central and eastern Europe, and Libyan desert glass found in areas in the eastern Sahara, the deserts of eastern Libya and western Egypt are notable examples. Vitrification of quartz can also arise when lightning strikes sand, forming hollow, branching rootlike frameworks called fulgurites. Trinitite is a glassy residue formed from the desert floor sand at the Trinity nuclear bomb test site. Edeowie glass, found in South Australia, is shown to originate from Pleistocene grassland fires, lightning strikes, or hypervelocity impact by one or several asteroids or comets.

A section of volcanic obsidian glass

Moldavite, a natural glass formed by meteorite impact, from Besednice, Bohemia

Tube fulgurites

Trinitite, a glass provided by the Trinity nuclear-weapon test

Libyan desert glass