Lead crystal
Lead crystal is a term for smooth or cut lead glass . The term “lead crystal” is misleading because it is not a crystal but a glass , an amorphous solid.
It is a jewelry glass made from quartz sand , potash and red lead ( ) and is often used as an imitation gemstone for rhinestones .
Lead crystal is also a synonym for high-quality utensils made of lead glass, especially drinking glasses for wine and sparkling wine , carafes , candlesticks, bowls, cans, vases and cake platters. Furthermore, jewelry and decorative objects such as busts, miniature models, crystal hangings of chandeliers , etc. are made from lead crystal.
There are two methods of making colored lead crystal. The cheaper method is to paint the glasses with special colors that remain permanently bonded to the glass through a subsequent firing process.
High-quality colored lead crystal glasses are produced using the so-called overlay technique. During production, the transparent glass is coated with a different colored liquid glass and then shaped. By partially sanding away the colored outer surface after cooling, colorful glass structures are created. Such glasses are often made by hand and are accordingly expensive.
Lead crystal traditionally comes from the area of the Bohemian Forest, i.e. from the border area between Bavaria and the Czech Republic . It was invented in the Jizera Mountains , where it is still made in factories today. On the German side, the centers of lead crystal production are located in the Bavarian Forest and in the Upper Palatinate Forest . The reason for the concentration in these forest mountains can be seen, besides the quartz deposits, in the fact that there was wood here for the high consumption of wood required for glass production, especially for the production of potash (see Bavarian pile ).
In Germany, lead crystal is now also produced industrially by machine-pressing the glass or blowing it into molds. This creates the typical shape of the glass, and the grinding process is no longer necessary. The surface is then etched in hydrofluoric acid. One speaks of the acid polish. The cheaper and more environmentally friendly fire polish is also used for smooth glasses without a cut, whereby the glasses are smoothed by heating the surface evenly.
health
Lead is harmful to health, and in principle it is possible for lead crystal glasses to release small amounts of lead to the food they contain. Whether this happens in relevant quantities depends primarily on the quality of the glasses, i.e. the accuracy of the production process and the nature of the substance (e.g. temperature, pH value, solvent concentration) that comes into contact with the glass. This is why the responsible authorities regularly examine products made of lead crystal for the solubility of the lead they contain, with most samples not emitting any harmful amounts of lead.
Individual evidence
- ↑ http://www.lgl.bayern.de/publikationen/doc/jahresberichte/2005/kapitel_d_2005.pdf ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Archive link ( Memento from December 31, 2014 in the Internet Archive )
