Crystal is a chemical compound of barium oxide or lead oxide with glass. This material is used for the manufacture of various dishes. Lead increases the strength of glass, making it the most dense, resistant to physical damage.
A bit of history
The history of crystal begins in the 17th century in England. Then King Jacob I forbade everyone to use wood in industry. According to his decree, it is necessary to abandon the use of this type of raw material.
Kilns began to be heated with coal. One of the masters G. Ravenscroft, who worked with glass, noted that the dishes in the ovens became transparent. He continued experiments and received a new material - crystal. This happened in 1676.
The characteristics of this material will depend on its grade. Consider them:
- A valuable variety of crystal is Bohemian, the material contains glass, which is made from calcium, potassium. In addition, barium is used instead of lead in this case.
- If the glass is combined with barium, while the proportion of the element will be at least 18%, then you can get the so-called bariumcrystal is a very common variety.
- If the composition contains no more than 24% lead, then it is commonly called low-lead.
- In the usual classic grade of crystal, the amount of lead is not more than 30%.
There is also rock crystal, but it has nothing to do with glass. This type of material is one of the varieties of quartz. Rock crystal is not used as a material for the manufacture of tableware. This type of crystal is very valuable. It is used by jewelers to make jewelry.
It should be noted that many people are worried that such crystal tableware can be harmful to human he alth, since it contains lead. However, there is no need to be afraid of this, since after processing this element loses all toxic properties.