Long before humans learned how to manufacture glass from raw materials, people fashioned tools and weapons from naturally occurring

glasses. Several types of natural glasses were used including tektites, obsidian, and pumice. Tektites are small ovalshaped pieces of glass believed to be from meteors. Obsidian, or cooled lava, is a glassy volcanic rock. And pumice is a foamed glass formed when gases are released

from lava as it cools. Among the first glass artifacts were knives and arrowheads of flaked obsidian dating from Paleolithic times. Among the

oldest pieces of synthetically manufactured glass known is a bead found in Egypt dating back to about 3500 BC. Most historians indicate that

the birthplace of man-made glass was in Egypt or Mesopotamia prior to 3000 BC.   It has been speculated thatglassmaking was accidentally

discovered while cooking in a sandy, alkaline environment. More likely glassmaking came about as an offshoot of metalworking. Silicate

impurities in metal ores would have separated during refining and formed an intriguing glassy slag. Another likely scenario may have been

from experimentation with ceramic glazes that were developing during approximately the same time period.

The Egyptians became excellent workers of glass and produced colored glass sticks as raw materials for glass objects such as glass vessels, glass eyes, beads, mirrors, and ornaments. The art of glassmaking died out in about 1200 BC and did not reemerge until about the 7th

century BC. During the 4th to 2nd century BC new technical and artistic developments allowed for the making of gold sandwich bowls in which

a layer of gold leaf was trapped between two layers of glass. Other developments of this Hellenistic period included the manufacture of mosaicglass rods and cameo glass, a two-layer glass that could be carved. It was the Romans who took the Egyptian’s knowledge of glass working

and raised it to a new level of excellence. When the technique of glass blowing was invented in the first century AD, glass quickly became

an object of common use throughout the Roman Empire because it was inexpensive and easy to produce. Techniques perfected by the Roman glass workers were soon spread throughout Europe and everything from blown glass vessels to cast glass windowpanes were produced. The Romans also became expert in coloring glass and modifying the reflective nature of the glass surface. Glass making centers arose in Italy

and glass was exported as far away as Britain. By the fourth century, different glass making centers throughout the East and the West were developing their own particular regional styles. As a result of barbarian invasions after the 5th century, glassmaking experienced somewhat of a

decline and it became a less centralized activity. This gave rise to more widely distributed yet smaller glass centers throughout Europe.

During the Medieval Period, glassmaking was dominated by the demand for colored window glass for churches and cathedrals. The earliest

surviving painted glass dates from the 10th century in Germany but it is suspected that painted windows date back to even earlier times. In the late 13th century a strong glass industry emerged in Venice. Techniques for making stemmed glasses and vessels, mosaic glass used to

produce millefiori glass, and ornately decorated glass objects were fiercely protected by laws which prohibited glass makers from practicing

their skills outside of Venice. Eventually, during the 16th century, the Italian knowledge of glass working did spread throughout Europe

influencing glassmaking in Vienna, Sweden, England, and Bohemia. By the late 16th century Bohemian glass began to develop a new style

which involved the cutting and engraving of glass. This was the beginning of the famous German “crystal”industry. The Germans also

introduced less expensive methods for producing colored glass by coating the outside of a clear glass vessel with a layer of colored glass.

Glassmaking was introduced to North America in 1608 at Jamestown. Most of the early glass produced there was sent back to England. A number of other glass factories were founded including one begun by Baron Stiegel in 1763 in Manheim, Pennsylvania. Over the years since the American Revolution a number of glass manufacturers grew up and died out. Many came to influence modern day glassmaking in the United States and they include Owens Illinois Glass Company, Wheaton Glass Company, Kimble Glass Company, Tiffany glass, and the Steuben

Glassworks in Corning, New York.Today glass is one of the most common substances in home and industry, and, at the same time, one of the most intriguing. Its hardness is evident in windowpanes and jars; its brittleness is unfortunately seen with table glass and light bulbs. Yet, glass is not a solid! It has little internal crystalline structure and therefore we call it amorphous. Usually it is described as a super cooled liquid.

Source: Dr. Patricia Hill, Millersville University