Aleš Lombergar

Basically, sand heated up will create glass.

Glass ingredients
Pure silica (SiO2) has a melting point of about 2,000° C (3,632° F). While pure silica can be made into glass for special applications (see fused quartz), other substances are added to common glass to simplify processing. One is sodium carbonate (Na2CO3), which lowers the melting point to about 1,000° C (1,832° F); “soda” refers to the original source of sodium carbonate in the soda ash obtained from certain plants. However, the soda makes the glass water soluble, which is usually undesirable, so “lime” (calcium oxide (CaO), generally obtained from limestone), some magnesium oxide (MgO) and aluminum oxide are added to provide for a better chemical durability. The resulting glass contains about 70 to 72 percent silica by weight and is called a soda-lime glass. Soda-lime glasses account for about 90 percent of manufactured glass.

As well as soda and lime, most common glass has other ingredients added to change its properties. Lead glass, such as lead crystal or flint glass, is more ‘brilliant’ because the increased refractive index causes noticeably more “sparkles”, while boron may be added to change the thermal and electrical properties, as in Pyrex. Adding barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion, and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern glasses. Large amounts of iron are used in glass that absorbs infrared energy, such as heat absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs UV wavelengths (biologically damaging ionizing radiation).

Glasses that do not include silica as a major constituent are sometimes used for fibre optics and other specialized technical applications. These include fluorozirconate, fluoroaluminate, and chalcogenide glasses.

In 2006 Italian scientists created a new type of glass using extreme pressure and carbon dioxide. The substance was named amorphous carbonia(a-CO2) which has an atomic structure resembling that of ordinary window glass [1].