Despite the fact
that the age of glassmaking is estimated at 6 thousand years, people learned to
found transparent and colorless glass only at the beginning of the Cristian era. Prior
to this, opaque colored glass in various tones was made and mainly small items
were made from it: beads, bracelets, buttons, rings, signets, chess pieces,
etc. Antique glassblowers began to widely use cold glass processing: embossed
carving, engraving, grinding.
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| Ancient Chinese Glass Bead |
As soon as the transparent
glass was obtained, glassmakers began to strive to make window plates out of
it. Scientists suggest that the window glass was initially colored. This is
explained by the fact that it was very difficult to obtain a clear glass since
the raw materials usually contain various impurities that give the glass color.
Especially
often iron compounds are in the raw materials.
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| Modern Window Glass |
In addition, the
receipt of plates for glass covering of windows was very difficult. Making
hollow products of a rather complex shape by blowing was a simpler task for a
person than obtaining sheet glass. This problem was solved only by the end of
the Middle Ages. During the archeological dig of Pompeii, buried under the
ashes of the volcano of Vesuvius in 79 AD, it was established that in very rare
cases glass plates were inserted into the windows. And they were quite thick.
Apparently, Italian glassmakers had not learned how to make thin sheet
glass.