Most people think of glass as a man-made material; however, it has always been found in nature. Obsidian, or volcanic glass, occurs when molten material, such as lava from a volcano, cools rapidly and doesn’t have time for crystals to form. Ancient man used obsidian for cutting tools like arrowheads and blades as well as for jewelry and money. Another natural glass, desert glass, was created by the intense force and heat of meteorites that hit the earth millions of years ago. And fulgurites, which are brittle tubes of melted sand, are made when lightning strikes that substance.
According to archaeological evidence, the first man-made glass was created about 4,000 years ago in Eastern Mesopotamia and Egypt. Ancient people discovered how to use a mixture of sand, soda and lime…