Glass is a fascinating material that has been used by humans for centuries and viewed in different ways throughout history. It has mysterious characteristics and can be utilized in incredible ways for both function and decoration. This post will give you a brief overview of the discovery of glass, how it’s been used through the ages and discuss the future of glass. We hope this gives you further insight into this incredible medium!
What is Glass?
Glass is an extremely unique and interesting substance. It is considered to be its own state of matter as it is neither a liquid nor a solid. The atoms are arranged in a rigid structure like crystals, but are more disorganized, like those in a liquid.
Structure of the Three States of Matter & Comparison of Quartz and Glass Structure (source)
Because of the unique structure of glass, there is debate about whether it is a supercooled liquid or a solid. As stated before, glass isn’t a liquid or a solid- it is an amorphous solid, which falls between the two. You can read more about this as well as why glass is often believed to be a liquid, in this article.
Glass is created by heating up a mixture of dry materials referred to as former, flux and stabilizer. Former is the main component of glass and has to be heated at an extremely high temperature to become viscous. Though different materials can be used, Silicon Dioxide, or silica, is the compound most commonly used as former and gives glass its basic structure and characteristics. Other ingredients need to be added to silica to change its properties and make it a more stable material. Flux is added to help the former melt at lower temperatures. Soda ash or potash are typically used. The final ingredient is the stabilizer, which keeps glass from dissolving, cracking or developing unwanted crystals. Calcium oxide in limestone is the most common stabilizer. The combination of these ingredients is called batch and it is heated in the furnace at about 2400 degrees Farenheit.
Since glass is created from heating up a mixture of these materials, it is actually a naturally occurring substance. A type of volcanic glass, called obsidian (shown left), is formed when lava rapidly cools down and has minimal crystal growth. Obsidian was used in prehistoric societies to make tools, weapons, jewelry and money. It is also possible for glass to come from meteorites that release so much energy that the material it lands on is thrown into the air and goes into a molten state, forming lumps of glass called tektites.
Furthermore, different ingredients can be used to create different types of glass with different types of characteristics. Soda-lime glass, like we use in the studio, is the most common type of glass. It’s made from silica, sodium oxide, lime, magnesia and alumina. This is an inexpensive, chemically stable, hard and workable glass used for items like window panes and bottles.
In comparison, borosilicate glass is made of silica, boron trioxide, soda and alumina. This results in a glass that has a high resistance to changes in temperature and chemical corrosion, but more expensive than soda-lime glass. Borosilicate glass is used for items such as bakeware, car headlights and chemical glassware.
First Manmade Glass
Now that we have an idea of what glass is, how did people figure out how to make it?
There are some romanticized stories that the discovery of glass occurred around 5000BC on the beaches of Syria when merchants used their cargo to hold up cooking pots causing a mixture of soda-rich natron and sand to melt and create glass. These stories are not regarded as being accurate mainly because a cooking fire would not get hot enough to reach the temperature required to melt glass. It is far more likely that glassmaking evolved from other crafts such as ceramics, which uses glazes similar to glass, or metallurgy, which requires separating metals from impurities called "slag" which contains materials that are used in the ingredients used to make glass.
Archaeologists have found manufactured glass in Egypt and Eastern Mesopotamia dating back to 3000BC as well as glass vases dating back to 1500BC indicating the existence of a hollow glass industry. It is believed that the first glass was most likely produced in Egypt and that glass industries developed independently in Egypt, Mycenae, China and North Tyrol around the same time. The first manual for glassmaking was found in the library of King Ashurbanipal of Assyria and dates back to 650BC. The creation and use of glass was very slow and costly. Glass was seen as a luxury and glassmakers were held in high esteem since not everyone had the skills and knowledge to melt glass. Glass shops were typically in larger cities where royalty and aristocrats could offer patronage. These trends changed when the revolutionary technique of glassblowing was discovered.
Discovery of Glassblowing & Expansion of Glass Production
In the 1st century BC, the first blowpipe was created in Syria. This opened up a world of new possibilities for glass production and made it cheaper, faster and easier. Glass production expanded to the Roman Empire from Italy and glass workshops were found around the Empire. With improvements in the production of glass, many types of glass vessels and containers were being made with great variations in color and decoration. This also resulted in a division of glassmaking into the mass production of everyday utensils and the manufacturing of elite decorative objects. Decorative objects were distinguished not by the exclusivity of the material but by the exclusivity that came from the skill of the craftsman who created the piece. This encouraged craftsman to find new ways to set apart the form and functionality of their glass, leading to the creation of new techniques.
Cage Cup from Roman Empire. 300–399 AD
By 1000AD, Alexandria in Egypt was the most important center for glass manufacturing upon the discovery of clear glass. This led to glass being used in architecture for the first time throughout the Roman Empire. Glass was also being traded widely and openly accepted, which caused it to loose it’s mystic and elite status. With the decline of the Roman Empire came the decline of glass and much of the knowledge of the craft disappeared from the West, with advanced techniques continuing only in the Byzantine Empire and the Middle East.
By the eleventh century, knowledge of glassmaking made its way back to Italy and Venice become a center of glassmaking. In 1271, the first legal regulations for glass-blowers were made. In 1277 an agreement between the Doge of Venice and the Prince of Anitoch was created to aid the exchange of technology and raw materials and secrets of Syrian glass production made their way into Venice. A glassmakers’ guild was founded and in 1292, and all glassblowers were banished to the island of Murano with the official reason being that there were so many workshops that there was a danger of fire. However, there are some stories that claim this was to protect the secrets of glassmaking and those who left or revealed those secrets would be put to death. It is unknown if there is truth to these rumors.
Glassmakers started making new types of glass such as cristallo (seen left), a totally clear, colorless glass, and lattimo, or milk glass, which has an opalescent look. They developed other techniques as well and Venice had a monopoly on the creation of large mirrors, which gave the city prestige and an economic boost. During the Renaissance, the Venetian glass industry saw the same esteem the Roman industry held during the time of the Roman Empire. Glass was once again viewed as mysterious and those who knew the secrets of it held economic power. The industry continued to expand and by the end of the sixteenth century the revived knowledge of glassmaking reached all of Europe and the Middle East. The fragile style of Venetian glass fell out of style and by the seventeenth century, the center of glass production move to Bohemia. Bohemian cut glass was much thicker and less fragile and found popularity along with enameled or painted glass. Around this time, North America developed its own glass production as well.
Industrialization of Glass
Glassmaking in America started in 1608 in Jamestown, VA. Glass was a symbol of wealth and was not found in most households. The first glass factories showed up in New York and New Jersey over a hundred years later, which saw the creation of more utilitarian glass products such as wine glasses, decanters, punch bowls, and candlesticks.
The Crystal Palace at Sydenham (1854)
The Industrial Revolutions of the 1800s brought about further advances in the manufacturing of glass. Synthetic glasses with improved properties were being made. Many machines were created to create different types of glass. In 1827 the glass pressing machine was invited, allowing for mass produced and inexpensive glassware. Other industrial processes were created, such as float glass, cylinder blown sheet glass, and rolled plate glass. Machines allowed for glass to made in large sheets to be used for huge windows like those that made up the Crystal Palace, the first building made of glass.
Art Nouveau & Tiffany Glass
Despite the mass manufacturing of glass, it was also being used in decorative arts. The nineteenth century Neo-Classical movement brought back cameos from the Romans. Glass was utilized greatly in Art Nouveau and Louis Comfort Tiffany created his famous Tiffany glass. In the twentieth century most glass was still being made in factories but some glass artists started to classify themselves as fine artists and the market for ‘art glass’ started to grow.
Studio Glass Movement
With the growing interest in art glass and the desire for glass artists to be considered fine artists, in the 1960s the United States saw a rise of glassblowers working out of their own studios with smaller furnaces rather than in factories. This movement spread into Europe, the UK, Australia and Asia and an emphasis was put on the artist as the designer and maker of one-of-a-kind objects.
Chihuly Garden & Glass
In 1962, Harvey Littleton spurred on a contemporary glassblowing movement, which would be referred to as the American Studio Glass Movement. This movement would generate some of the most important contemporary glass artists including Marvin Lipofsky, Sam Herman and Dale Chihuly. The rise in popularity of glass art also encouraged the creation of glass schools such as Philchuck Glass School, Pittsburgh Glass Center and the Corning Museum of Glass.
Today glass is so commonly used, we hardly think about how much we rely on it. Technology relies heavily on the utilization of glass and without advances in glass we wouldn’t have amazing technology like our smartphones or huge telescopes in space. Medical science is even figuring out ways to generate bone from glass. This article from The Atlantic give further insight into the many ways glass has been used throughout history and ways it will be used in the future. Glass is a truly remarkable substance that can be used in functional ways to improve our lives or to add beauty through decoration.
This post was just meant to give a quick overview of the evolution of glass throughout history. Below are some great resources for you to learn more. Keep an eye out in the future for more posts discussing specific glass movements and glass technology!
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