A small, but important type of glass, aluminosilicate, contains 20% aluminium oxide (alumina-Al2O3) often including calcium oxide, magnesium oxide and boric oxide in relatively small amounts, but with only very small amounts of soda or potash. It is able to withstand high temperatures and thermal shock and is typically used in combustion tubes, gauge glasses for high-pressure steam boilers, and in halogen-tungsten lamps capable of operating at temperature as high as 750°C.
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Many glass making terms have entered the language: 'Shut yer gob': a molten lump of glass is called a 'gob' to which the glass blower attached a tube to blow the glass into shape. The blower had to blow hard which made his cheeks very large. Today someone with a big mouth is told they have a big gob.