Winter is a popular time to take a tropical getaway and enjoy a white sandy beach. What you may not know is that common beach sand is actually the primary ingredient in the creation of glass. Not all sand, however, is created equal. The properties sought after for the perfect beach getaway — fine, smooth sand that stays cool under your feet—are actually the same properties that make for the best glass.
To achieve the highest quality glass in both transparency and color, it is necessary to use silica sand, comprised mostly of quartz. While white sand can be an indicator of the presence of silica, it could also be the result of tiny pieces of coral and other sea creatures. This is more common in many of the low-latitude beaches.
The sand at Whitehaven Beach in Australia, however, consists of 98% pure silica. It is so white that it actually reflects the heat and remains cool to walk on. In the United States, Siesta Key in Florida is well-known for its white (silica) sand beach.
The Chemical Components of Ordinary Glass
While applying heat to pure silica alone in its natural state can create glass, it has an extremely high melting point and is difficult to shape in its molten form. In 1945, when US Scientists were testing a nuclear bomb in the New Mexico desert, the explosion actually turned the nearby sand into glass. To be able to produce glass at a lower temperature, however, additional compounds, including soda ash (sodium carbonate) and limestone (calcium carbonate) are added. The soda ash lowers the temperature necessary to make glass, but it also produces a glass that would dissolve in water. The addition of limestone stops this from happening. The final result is soda-lime-silica glass, the most commonly used glass today.
Additional chemicals may also be added depending on the purpose of the glass. When producing crystal, for example, lead oxide is added to provide sparkle. True crystal, in industry terms, must contain at least 24% lead. Lanthanum oxide is used in glass eyewear for its refractive properties. To achieve various colors, iron, copper oxide or sulfur can be added to the glass. A slight green hue to a sheet of glass is the result of iron.
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