Lead Crystal Stemware

Lead crystal, (also called crystal), is lead glass that has been hand or machine cut with facets. Lead oxide added to the molten glass gives lead crystal a much higher index of refraction than normal glass, and consequently much greater "sparkle".

The presence of lead also makes the glass softer and easier to cut. Crystal can consist of up to 32% lead, at which point it has the most sparkle. The higher lead content also makes it much more difficult to form crystal during blowing.

Englishman George Ravenscroft discovered crystal in 1676 and today many producers for high-end stemware for wine and water are using lead glass in their products. Often it is used as distinguishing factor in marketing and sales.

Some preliminary testing indicated that over time significant amounts of lead can migrate from lead crystal containers into beverages stored in them. Lead crystal typically contains 24-32 percent lead oxide.

The amount of lead migration was measured for port wine stored in lead crystal decanters. After two days, lead levels were 89 micrograms. After four months, lead levels were between 2,000 and 5,000 micrograms. White wine doubled its lead content within an hour of storage and tripled it within four hours. Some brandy stored in lead crystal for over five years had lead levels around 20,000 micrograms.

To put this into perspective, EPA's lead standard for drinking water is 50 micrograms per liter. Citrus juices and infant formula leach lead from crystal just as effectively as alcoholic beverages.

Resourcers:
Wikipedia
PubMed - Lead migration from lead crystal wine glasses
Determination of Lead Leaching ...