“Mirror, mirror upon the wall, which material is the most important of them all?”

“You're looking at it kid,” the mirror replied.

Can this be true? That out of all the thousands of materials we have discovered throughout the ages of our civilization, glass is the most remarkable?

If, today, we removed all glass from our planet, then mirrors, lenses, drinking glasses, and bottles would all disappear. As would our glass fibers and, with them, our ultrafast telecommunications. With all these technologies, we have alternative materials. However, glass is irreplaceable as our main transparent protection against the wind, rain, heat, and cold, and is thus the key to our trains, planes, automobiles, and, of course, buildings. There is nothing remotely as good as glass for this task. Even the strongest and most transparent acrylics are too soft to withstand the erosion of the wind, and too prone to degradation by ultraviolet radiation. Is this why we build tall glass temples in all our major cities? To praise this cold, brittle, awkward, heavy material that is humanity's most important shield?

No. Such an analysis is too literal, for glass's impact on our culture is much more subtle.

Glass was discovered very early in our civilization. For thousands of years, it was highly prized for its aesthetic virtues, but since early formulations had little strength, it was used as jewelry and for little else. In China and the East, their expertise in ceramics far eclipsed their knowledge of glass, and so it was ignored. But in the West, perhaps fortunately, the opposite occurred, and glass was nurtured from a friable, cracked, fake gemstone into lustrous, strong, brilliant windows and magnificent chandeliers. The material became highly prized and, by the Renaissance, the arts community had reached a sufficient level of sophistication to make a telescope for Galileo to view the heavens.

Thus, an aesthetic urge ushered in the biggest change in human thought for a thousand years. Later, glass lenses changed our view of inner space with the invention of the microscope and many other scientific instruments. The transparency and inertness of glass pushed chemistry forward by allowing color changes of chemical reactions to be monitored and gas evolution to be observed, so much so that glass became the essential material for chemistry labs. Physicists used glass in the form of prisms, lenses, and mirrors to understand optics and interrogate the nature of light and quantum phenomena. Later, it was instrumental in the invention of photography, television, and film. The image of a wizard using glass in the form of a crystal ball to see into the future sums up the mercurial influence of this material on our visual culture.

But glass did more than protect us, inspire us, extend our senses, and transform science. It transformed beer.

In Bohemia in the 1840s, it became possible to mass produce drinking glasses. Hitherto, most people had to drink from opaque materials such as wood, metal, or ceramic. As a result, for the first time, beer drinkers were made aware of the cloudiness and murkiness of beer. Before this, they cared only for the taste, but now a new, clear beer started to replace the black and brown beers that had existed before. The new beer was less tasty than the old beer, but looked more beautiful. It was called lager and is still unfortunately with us today. Ironically, this type of beer is now mostly drunk from cans where its clarity is masked. A further irony is that the type of beer that it almost wiped out, stout, has used the aesthetic virtues of glass to reverse its fortunes by creating the unique image of a black liquid topped by a contrasting white froth.

This type of intricate interplay between aesthetic and physical properties is common in the history of materials, and is the key to understanding the ancient materials game of ‘rock, scissors, paper’. Rock beats scissors because of its superior hardness; scissors beats paper because of its superior strength; but paper beats rock because of its cultural power. It's odd that glass is not included in this game, but surely this is because it beats them all.

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DOI: 10.1016/S1369-7021(05)71059-2