The main materials that are used to make glass are sand, soda ash and limestone. These are often mixed with other materials to give the glass specific properties. For example, iron or carbon can be added to the mixture to make the glass a different color.
The main ingredient in glass is sand. This is because sand is made up mostly of a substance called silica, which is need to make glass. Silica sand comes from various countries including Australia, Indonesia, Malaysia, Vietnam, China, India and Egypt. This sand is mixed with the other ingredients, particularly the soda ash and limestone, and is melted in a furnace at temperatures that are as high as 3,092 degrees Fahrenheit.
The raw material mixture feeds constantly into the furnaces at glass manufacturing facilities, and takes about 24 hours to be turned into glass. It comes out of the furnace in liquid form and goes to a refiner.
There are many different ways to alter the composition of glass, as well as its appearance and other properties. For example, glass can be coated, treated to withstand high temperatures or decorated. It can be molded into all sorts of shapes while still in a melted state, and it can changed by making it cool at different rates.