Woman enjoying her clean windows

I clean a lot of glass, but how is glass made?

Glass is used everywhere. It is an integral part of our lives, from the window we peer out of to the glass we drink out of. People have been creating glass for centuries, and nature has been making it since the earth’s formation.


We take it for granted, but how did it get from the ocean to your window? Glass is made by melting sand and combining it with limestone and ash. It can be further combined with other chemicals to create different types of glass. Glass can be made naturally by lightning and volcanic eruptions.


Keep reading because we will explore a brief history of how glassmaking has changed over the centuries. Oh, and stick around for the fun part, as I have compiled a list of facts about glass.

The History of Glass Making (Study hard! There will be a test later!)

Archaeological finds have dated the first man-made glass to 2500 BC from the Mesopotamia area. (The first glass cleaning business was probably started at the same time.) Glass vessels began appearing in 1450 BC in Egypt during the reign of Thutmose III. Glassmaking in these two areas featured a soda-lime-silica composition. This method traveled to Phoenicia and from there to Cyprus, Greece, and the Italian Peninsula.


Following the conquests of Alexander the Great in the 4th century BC, glassmaking spread to the east, including India. In Alexandria (around 100 BC), the process of creating open beakers and shallow dishes was developed. Around the beginning of the Christian era, the Phoenicians began glass blowing.


 Roman and Egyptian Glass Making

The Romans and Egyptians most likely used sand mixed with ground seashells as raw materials for silicon and lime. Hardwood ash was the source of the soda. These two groups also showed remarkable ingenuity in how they used metallic oxides as coloring for the glass.


After AD 200, glassmaking skills in Europe declined considerably, remaining far below those of the Romans for a thousand years. The stained glass windows that began appearing in churches in the 12th century did not reach their peak until the 13th and 14th centuries.


Following the decline in glass making skills, the Venetians redeveloped all Romans’ skills. (including how to make Venetian blinds!) Most of their creations were soda-lime glass. By the 15th century, they developed new materials, colored glass types, and techniques for decoration.


In 1453, following the capture of Constantinople by the Turks, the Venetian glass trade fell. Venetian glassmakers immigrated to other European countries.

The 18th and 19th centuries’ chemical revolution brought a greater understanding of glassmaking principles. The following were all developed (contributing to the establishment of a large-scale industrial supply of purified raw materials):


    • Systematic quantitative chemical analysis
    • Chemical formulas
    • Chemical equations

For the record, I don’t make glass. Sorry. Not. But I do clean glass really, really well. Click here to be taken to the home page and explore more on this site. 

12 Interesting Trivia Facts about Glass

What would this blog post be without some glass fun facts? So the next time you’re at a party, you can impress your friends with your knowledge about cocktail glasses!

Fact #1: Glass is Made from Liquid Sand

Ordinary sand is mainly composed of silicon dioxide. When it is heated to its melting point of 1700 ℃  (3100º F) it turns into liquid sand. When it is allowed to cool, it becomes an amorphous (shapeless and flowing) solid, which is physically similar to a liquid and a solid.


Fact #2: Chemicals Change the Properties of Glass

Manufacturers add chemicals to liquid sand to create a desired result in the final glass product. For example, cobalt salt is added to produce blue glass while chromium- or iron-based chemicals produce green glass. Boron oxide is added to make oven-proof glass. Lead oxide is added to make an easily cut fine crystal glass.


Fact #3: Glass Shatters Faster than the Speed of Sound

We all know that glass can break easily under the right circumstances. But what is not commonly known is that the cracks move at a 3,000 miles/hour speed. To put that into perspective, the speed of sound in dry air is only 767 miles/hour.


Fact #4: Tempered Glass will Shatter into Granular Chunks

Tempered glass is manufactured through the application of controlled chemical or thermal treatments. These treatments make the glass four times stronger than regular glass. Because of the difference in the way it is manufactured, it will shatter into granular chunks instead of the jagged shards that regular glass shatters into.


Fact #5: Optical Fibers can be Made of Glass

While some optical fibers are made of plastic or polymer, many manufacturers use glass to produce Optical fibers. They can transfer data at speeds up to 10 Gbps.


Fact #6: Glass is a Natural Phenomenon

While humans have been producing glass since 2500 BC, nature has been making it since the earth was formed. Naturally occurring events like lightning and volcanic eruptions can produce glass.


Fact #7: Bulletproof Glass

Bulletproof glass is manufactured with several layers of laminated glass. With multiple types of glass, different layers of polycarbonates are also used. This type of glass is designed not to shatter if there is any impact.

The glass’s thickness ranges from 19 to 89 mm (3/4 of an inch to 3.5 inches). The thicker it is, the safer it will be. However, it will also be heavier. There is no bulletproof glass that is completely indestructible.


Fact #8: Glass is Fully Recyclable

Glass is nearly 100% recyclable, meaning that you can recycle a piece of glass without losing the purity or quality of the glass. It is a risky process and not very cost-effective. Because of this, most countries do not make it a priority.


Fact #9: Glass Windows Became Common in the 1700s

In the 1700s, people started using glass windows in England. Before this, the expense was too great for them to afford to use glass. Going back in history, we find that the technology to incorporate glass in windows was first invented by the Romans in 100 AD.


Fact #10: Glass has Unique Properties

Glass is known for having several unique properties:

  • First, it’s transparent with a smooth surface
  • Glass is erosion-resistant
  • Glass can transmit, reflect, and refract light

Glass is also chemically resistant and corrosion-resistant.


Fact #11: Largest Museum of Glass Art

The Corning Museum of Glass is the largest museum dedicated to glass in the world and was established in 1951. It houses over 50,000 glass objects, with some of its collections over 3,500 years old.

Interestingly, the owner of this museum is Corning Inc., a renowned glass company. Most smartphone manufacturers use Corning Gorilla Glass on their devices.


Fact #12: How much glass weighs

A solid cubic foot of ordinary glass will weigh from 100 pounds up to about 185 pounds. A window that is 4 feet wide by 8 feet tall and ¾ of an inch thick would weigh approximately 320 pounds and cost up to $5,000 to replace if broken.

The window cleaning business is a service business. Here is a list of other excellent local service businesses.

Living room with large windows

They make the glass and I clean the glass. Call for free estimate or to schedule to have your windows washed.