A mixture of special sand (silica) with traces of other elements such as boron, phosphorus, lead, and so forth. These ingredients are melted together at a temperature of about 3000 degrees Fahrenheit (1649 degrees Centigrade). The newly formed glass, when cooled, is noncrystalline, smooth, extremely hard and quite brittle. Volcanic heat has produced a form of glass called “obsidian,” and lightning, striking sand, sometimes fuses it into “fulgurites,” long, slender tubes of glass, often called “petrified lightning.”
When this unique substance was first made by man is not known. In Egypt have been found glass beads that archaeologists believe were made some 4,000 years ago, about the time Abraham was born. Job, who lived in the seventeenth century before the Common Era, names glass alongside gold for preciousness when he says: “Gold and glass cannot be compared to [wisdom].”—Job 28:17.
Egyptian artisans were skilled in molding, cutting, grinding and engraving glass. They knew how to imitate the colors of some of the precious stones. The Greeks and Phoenicians engaged in glassmaking and the Romans became skilled in it, also developing to a higher degree the art of glass cutting. A Roman vase, called the Portland Vase, said to have been made about 70 C.E., the year of Jerusalem’s destruction by the Romans, is now in the British Museum. It is reported as being valued at more than $50,000.00.
It is possible that the ancients were familiar with optical magnification by means of glass. A quartz lens has been found in the ruins of Nineveh, but some believe that if it was truly used as a lens, it was used only to focus the sun’s rays as a burning glass.