Page 41 - Curriculum Visions Dynamic Book

Coloured glass
Coloured glass is made by adding a variety of metal compounds to the melt, usually in quantities that comprise less than half of 1% of the glass. Soda lime glass is normally a very pale green, mainly because it contains impurities of iron. But to get a richer colour more impurities must be added. A rich red is obtained by adding cadmium sulphide and selenide. Cobalt is added to produce a deep blue glass. Brown is obtained by adding iron sulphide. It is used for some beer bottles. Manganese gives pink and violet colours.
Controlled
atmosphere Glass sheet
 This picture is a piece of Venetian glassware, which has been skilfully moulded at a temperature near the melting point of glass.
Diamond tipped cutting point
Roller
The glass is slowly cooled in a long chamber called the annealing lehr to allow the release of internal stresses in the glass
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