Glass silica has a wide variety of uses, including drinking vessels, windows, art and even communications. Much of human history has been characterized by the use of glass silica in various things, beginning with ancient Egypt and Mesopotamia using it to create glazes for pottery. It is made from natural ingredients, most often a mixture of quartz and sand. Glass silica is typically formed by heating some form of silicon dioxide and then cooling it rapidly so that it forms an amorphous, rather than crystalline, molecular structure. Silicon dioxide may also be integrated into Portland cement and used to create various earthenwares and porcelains.
Glass silica can be created from any form of silicon dioxide, though different forms subjected to varying processes will result in a wide variety of end products. One common type is soda-lime glass. This variety is commonly used to make a wide variety of drinking glasses, bottles and containers. It is also often used for windowpanes. Sand is commonly the type of silicon dioxide used to create this kind of glass, along with a variety of other components, such as lime and sodium carbonate. The addition of iron oxide can result in green or brown colored glass.
Lead glass and lead crystal contain varying amounts of lead in their mixtures. The addition of lead can result in a pleasing aesthetic look, since it results in the glass having a higher refractive index. While this type of glass, like all other glass, is not actually crystalline in nature, decorative pieces made from lead glass have commonly been referred to as crystal throughout history.
Fused quartz is a type of glass silica that can be created by heating quartz crystals. Since the crystals are typically free of most impurities, the resulting glass is often used for the mirrors in telescopes. Other common uses of this type of glass are in the creation of semiconductors, and as a component of halogen lamps. It is useful in semiconductors due to its high purity, and in halogen lamps because of its ability to withstand high temperatures.
Some optical fibers are created from forms of silica that are even more pure. Early methods involved using purified and powdered silicon dioxide. The silica powder, together with small amounts of other chemicals, would be heated to very high temperatures and then drawn out into extremely thin filaments. Other methods have since been developed, including one that utilizes sodium tetrachloride in a liquid state.
