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 the 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. By his decree, it is necessary to abandon the use of this type of raw material.
Furnaces began to melt with coal. One of the masters G. Ravenscroft, who worked with glass, noted that the dishes in the ovens became transparent. He continued the experiments and received a new material - crystal. This happened in 1676.
Crystal grade
The characteristics of this material will depend on its grade. Consider them:
- A valuable grade of crystal is Bohemian; the material contains glass, which is made from calcium and potassium. In addition, barium is used instead of lead.
- If the glass is combined with barium, while the element's share becomes at least 18%, then you can get the so-called barium crystal - a very common variety.
- If the composition contains no more than 24% of lead, then it is customary to call it low-lead.
- In an ordinary classical grade of crystal, the amount of lead is not more than 30%.
There is also rhinestone, but it does not apply to glass. This type of material is one of the varieties of quartz. Rhinestone 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 worry that such crystal glassware can be harmful to human health, as it contains lead. However, there is no need to be afraid of this, since after processing this element loses all toxic properties.