The History of Glass
Glass
The history of glass is an old, mysterious story. Natural glass has existed since the beginning of time. Obsidian is a natural black volcanic glass that was used by primitive people for tools, knives, arrowheads, and decoration. It is uncertain when and where man discovered combining enough heat with the right materials could make glass. Archeologists have dated the oldest man-made glass to about 7000 B.C. Glass’s natural properties are what create its sparkling brightness and often-translucent form.
Glass’s history has many uncertainties. The New Book of Knowledge states that according to the Roman natural historian Pliny (A.D. 23-79) glass was discovered along the coast of Syria. According to this account, some seamen stumbled upon glass when cooking there dinner. Since they could not find big enough rocks to place their cooking pots on, they used blocks of niter, a form of soda. After their fires died down, they found that the niter had fused the sand underneath into a glassy substance (“Glass”). After this discovery the craft was born. Early glass articles consisted mainly of small beads and charms. Glass was considered as a gem, valued equally as a precious stone. Not until the discovery of the blowpipe was glass changed from a luxury product into something that lower class people could afford and enjoy (“Glass”).
Glass is one of a few products that can be made from inexpensive raw materials. According to The New Book of Knowledge glass has a base of pure silica sand, which is composed of the mineral quartz, a compound of elements silicon and oxygen (“Glass”). In order to allow the sand (former) to melt more readily at a lower temperature of about 2600 degrees Fahrenheit, fluxing agents need to be added, like Soda ash, potash, and lithium carbonate. Fluxes however, make the glass chemically unstable, making it liable to dissolve in water or form unwanted crystals. Therefore stabilizers are also needed to make the glass uniform and keep its special structure intact. These include limestone, litharge, magnesia, barium carbonate, strontium carbonate, and zinc oxide (The Glassy State In-Brief Par 6-8). Other substances can be added to adapt glass for special purposes. Because of the iron present in all sand, glass naturally has a greenish cast. In order to decolorize the glass selenium (a non-metallic element somewhat like sulfur) needs to be added. This...