FAQs :: Bundesverband Glasindustrie e.V.

FAQs

When was glass first used?

Glass is one of the oldest materials to be used by mankind. Glass and materials containing glass exist in natural form (obsidian). They were either created during the lava cooling process following meteorite collisions or as a result of the high temperatures generated when lightening strikes. It cannot be said with any certainty whether glass was first produced in Mesopotamia, in Egypt or on the Levante Coast. The oldest piece of glass ever found by archaeologists in Egypt is dated at 4000 – 5000 B.C. This find shows us that glass was used in those days to coat clay vessels.

Where does the word glass come from?

The word glass is derived from the German word for amber (glaesum) and means "to shine" or "to glitter".

What are the properties of glass?

An ideal material with many advantages

Glass is a solid produced from a molten substance. From a physical viewpoint, glass is an undercooled liquid. At room temperature, glass is solid, at approximately 1,000 °C it is formable and at temperatures of between 1,400 °C and 1,650 °C it melts. Glass has many positive and practical properties which make it an indispensable packaging for foods, beverages or cosmetics, innovative glass fibre optic cables for data transmission and practical glass ceramic cooktops.

The properties of glass are listed below:

... it is a material made of natural and nature-identical raw materials.

... it is an inorganic melt product.

... it is a versatile material.

... it is a material that can be used for many different applications.

... it can withstand high temperatures.

... it is dimensionally stable yet still formable.

... it is an absolutely gas-tight packaging material, inert, tasteless and does not interact with other materials.

... it is 100% recyclable.

What is glass made of?

Glass is made exclusively from natural or nature-identical inorganic raw materials, the majority of which exist or can be produced in Germany. Essentially, a total of six natural raw materials are necessary to produce soda-lime glass: approx. 70 percent quartz sand (SiO₂), 13 percent soda ash (Na₂CO₃), 10 percent limestone (CaCO₃) and small quantities of dolomite, feldspar and potash. The choice and quantities of the raw materials used depend on the properties required of the finished glass product and the production process used. Not only the primary raw materials, but also processed pieces of old glass or cullets play a very important role in the glass manufacturing process. Glass is 100 percent recyclable. This means that used glass can always be reintroduced into the glass cycle for the production of new glass. Cullets have now replaced sand as the main constituent of container glass batches.

How does glass contribute to environmental protection?

Glass is 100 percent recyclable. It is produced on a cradle to cradle basis with waste glass being used to produce new glass. This conserves natural resources and helps to save energy. Between 30 and 95 percent of glass produced in Germany consists of waste glass. This reduces the energy required to melt the glass by up to 30 percent compared with processes which only involve the natural raw materials.