Tuesday 15 May 2012

CRYSTAL GLASS




LEAD CRYSTAL WARE
Lead crystal is glass in which lead had been put in instead of calcium. The production with calcium is defined as potash glass. Lead glass is made of 18-35 mol %(II) oxide (PdO). Today crystal glass has a minimum of 24 % PdO. Lead glass favoured by glass cutters.
As a matter of fact it should never been called crystal because it has no crystalline structure. It has only been called for historical and commercial reason to make it more popular. The name came from Venice where they named it crystallo referring to an imitation by Murrano glassmakers. It is still used today.
In Nippur they excavated the first piece of glass known as the blue glass. Dated back to 1400 BC
Glass making was also mentioned in clay tables when Assurbanipal reigned from 668-631 BC. On some Babylonian tablets was information how to do lead glazing in the 1700 BC.
Lead glass was made during the Han dynasty in China 206 BC - 220 BC. It was made to imitate jade and shaped into big or small figures or jewellery and some vessels.
It is assumed that the technique was brought over from the Middle East by glass-makers along the Silk Road. However, there is a difference between the West silica-natron glass and the unique China lead glass which suggests a different technique.
In Europe lead glass was used for colour glass especially mosaic, enamels, stain-glass paintings to be used to imitate precious stones.
George Ravenscroft (1618-1681) was the first producers of clear crystal glassware. Son of a merchant he had contacts in Venice. He changed the entire glass trade using his knowledge and money. England overtook Venice in the glass industry from the 18th century including the 19th century.
Ravenscroft started to use flint and named it flint glass but later on he switched to sand.
To begin with glass was sold by weight. It had such a success that in 1746 the British Government put on a high tax by weight. Instead of reducing the lead content the manufacturers produced highly decorative, smaller and delicate forms with hollow stems. They are now known as Excise glasses.
1780 Ireland was granted free trade and no tax. The glass-works moved to Dublin, Belfast, Cork and Waterford. The Government reintroduced the tax in 1825 and the industry declined until mid 19th century when it was stopped again.
From there on English Lead glass had been very popular in Europe, especially the wheel-cut glass.
In Holland the first lead crystal glass production started. By the end of the 18th century lead-crystal glass was produced in France, Germany and Norway.
1899 Anglo-Irish lead crystal overtook lime potash glass on the Continent. Glassware in Bohemia started to produce coloured glass and became very popular.Top of Form
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2 comments:

  1. Fascinating article about crystal glass. Its amazing how we rely on glass. I can't imagine bein without it, but of course it had to start somewhere. Really interesting. Thanks.


    http://nell-rose.hubpages.com/_3irgbjxgd6ylw/

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  2. Thank you, Nell Rose, for your wonderful and appreciative comment.

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