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facts about glass

Glass is natural
Glass is created by melting minerals together at high temperatures. Silica, a form of sand, is the main ingredient and is combined with soda ash and limestone melted in a furnace at high temperatures. Other materials and minerals can be added to produce different colours.

Glass can be made by nature
When lightning strikes silica sand, glass can be formed by the high temperature. These glass tube or ‘fulgurites’ are formed when lightning with a temperature of at least 1,800 °C melts the silica and fuses the grains of sand together; this only takes about a second!

Glass has been made for over 5,000 years 
From our earliest origins, man has been making glass. Archaeologists have found evidence of man-made glass dating back to 4,000BC in the form of coatings on stone beads. Around 1,500 BC the Egyptians made the first glass bottles in a state we would recognise today.

Glass packaging is pure
Glass containers are impermeable, air-tight, and transparent. You can see the freshness of food and beverages. Glass packaging can handle vacuum or high-pressure sealing, safeguarding against moisture and oxygen. This protects food and beverages from spoilage and bacteria.

Glass containers are lighter than ever
Today’s glass containers are more than 40% lighter than they were 20 years ago. Light weighting efforts continue throughout the industry.

Glass recycling has many benefits

  • Glass can be recycled again and again without ever losing its clarity or purity. Every ton of glass recycled prevents the quarrying of 1.2 tons of raw materials.
  • Bottles and jars manufactured in South Africa contain at least 40% recycled content, one of the highest percentages for packaging in South Africa.

Glass recycling saves energy
Making new glass from recycled glass uses much less energy than using raw materials. The energy saving from recycling just one bottle will power one of the following:

  • A computer for 25 minutes
  • A colour TV for 20 minutes
  • A washing machine for 10 minutes

If the average household recycled all their glass in a year, enough energy would be saved to power:

  • A computer for 5 days
  • A colour TV for nearly 4.5 days
  • A washing machine for 2.5 days

Glass recycling reduces greenhouse gas emissions
Recycling reduces the release of CO2 into the atmosphere, helping to minimise climate change. Every ton of new bottles and jars made using recycled glass rather than raw materials prevents the emission of 670 kg of CO2.

Glass is coloured by natural colourants
Colour can be obtained by simply adding small quantities of different oxides: 

Amber Glass – Amber is the most common coloured glass, and is produced by adding together iron, sulphur, and carbon.

Green Glass – Green Glass is made by adding non-toxic Chrome Oxide; the higher the concentration, the darker the colour.

Blue Glass – Blue glass is created by adding cobalt oxide, only a few parts per million is needed to produce a light blue colour such as the shade used for certain bottled waters.

You can read more about glass and recycling on these international sites: 

www.friendsofglass.comwww.gpi.org; www.o-i.com and www.britglass.org.uk