Updated November 5, 2023
The easiest way to tell if it’s lead crystal glassware or ordinary glass is to take a butter knife or other metal utensil and gently tap the glass; if it makes a drawn-out ringing sound, it is more than likely crystal; if it sounds more like a short dull “clink,” it’s glass.
Ordinary glassware (soda-lime glass) does not “ring” like lead crystal glassware because, with the addition of lead, the glass absorbs more energy when tapped and causes it to resonate/vibrate creating what some call a “ping.”
In addition, lead crystal weighs more than regular glass; there’s no mistaking the two.
Lead oxide added to molten glass is what gives leaded glass “crystal” the refractive qualities; glass without added lead has a refractive index of 1.5.
Leaded glass has a refractive index of 1.7 which is the point where light can be separated into its colors and therefore has a prismatic (rainbow) effect.
Due to its acidic nature, a teaspoon of white wine vinegar, when let stand for twelve hours in a regular glass, wine goblet, or any other leaded glass object, can show the presence of lead (if present) when tested with a 3M lead test kit.
However, it’s worth noting that as of October 2023, the 3M lead test kit is no longer in production.
Instead, the Dexsil Corporation of Connecticut produces a similar swab (pretty much identical chemical makeup) with the same Tartaric acid solution ingredient, which is used for lead testing.
You can view or purchase a lead test kit here.
This test can show that lead may be present, but not parts per million (ppm.)
You can also have your item tested by a lab that would run an XRF (x-ray fluorescence) analysis of wine glasses, glass bowls, or other crystal pieces; an analysis costs approximately $50 per test.
The XRF will detect the presence of lead, if any, and how many parts per million/ppm lead the crystal contains.
The XRF analysis can also detect any other heavy metals and the presence of hazardous elements in a crystal object as well.
Two other options are taking a suspected piece, pulverizing it, melting it down to find the lead content, or subjecting the item to strong acids that will ruin the piece.
There is one more test which can tell you if your glassware products contain lead, and that is to see if they flouresce under Ultra-Violet light.
Understanding the Glow: Using UV Light to Test for Lead in Glass
While tapping the glass and weighing it can give you a good indication of whether there’s lead in your glassware, there’s another, yet simple, method you can use to test for the presence of lead in glass:
Ultraviolet (UV) light testing.
This easy test hinges on the principle that lead in glass can cause it to fluoresce or glow under UV light.
What You’ll Need for the UV Light Test:
– A UV light source (commonly known as a black light)
– The glass item you wish to test
– A darkened room to clearly see the fluorescence
Conducting the Test:
1. Prepare Your Testing Area:
Ensure the room is as dark as possible. The darker the environment, the more noticeable the glow will be.
2. Safety First:
Before turning on the UV light, ensure you’re not directly looking at it, as UV light can be harmful to the eyes. Wear UV-protective glasses if available.
3. Examine the Glass:
Shine the UV light on your glass object.
Look for a distinct glow that may range from a chalky blue to a deep violet color.
This is indicative of the presence of lead, which fluoresces under UV light.
4. Interpret the Glow:
The brightness and color of the fluorescence can vary based on the concentration of lead and other metals/minerals within the glass.
A stronger fluorescence typically indicates a higher amount of lead.
Antimony also gives a blue glow under UV light, but is not as vibrant a color of blue.
Drinking from Lead Crystal Stemware
Drinking from lead crystal glasses from time to time should not sound any alarms, according to recent scientific studies, as the contents are not usually in the container long enough for the lead to leech out into the product being consumed.
A recently released (March 2022) research article in the Proceedings of the National Academy of Sciences shows that children born in the United States between 1951 and 1980 have a collective I.Q. point loss of 824,097,690 due to exposure to lead.
An estimated 170 million Americans alive today were affected by gasoline, paint, and other sources of the neurotoxin (lead) as children, resulting in an average loss of I.Q. of 2.8 points per person and a high of almost 6.0 points in some groups depending on what range of years in which they were born.
The article is available here:
While vintage glassware and leaded crystal glass can add a touch of elegance, their usage should be reserved for special occasions such as the Holidays and special drinks, but not for daily use.
Acidic and alcoholic beverages should not be left in leaded crystal decanters for any prolonged period of time to reduce the risk to human health; in fact, many leaded decanters have been shelved and replaced with something such as Crystalline Glass.
Leaving the product in lead crystal beverage containers such as a decanter can result in higher lead concentrations and increased health risks due to lead exposure.
If the product is consumed within a day, using leaded crystal stemware/glass should be fine; with that being said, there have been tests that showed traces of lead leaching out into the product at two days.
What is Lead Crystal?
First of all, there is no crystal in lead crystal; it is a term that goes back a long time, many years.
Lead crystal is glass with lead added to it.
Glass is an amorphous solid; it has no crystalline structure, such as quartz does.
When referring to lead glass, the term “Crystal” has remained in use because of its historical value, and the word “lead” can leave consumers with negative connotations.
The term Crystal glass originates from the Venetian word Cristallo which described the rock crystal that Murano glassmakers imitated; it dates to the 15th century.
George Ravenscroft’s 17th-century innovation of using high-purity silica from chalk deposits to create a potash lead glass with remarkable clarity gave rise to flint glass, which was historically known as “crystal.”
The glassware initially resembled rock crystal, and hence the term “crystal” was assigned to it.
However, due to health risks associated with lead, barium oxide has become a popular substitute in modern “crystal” glass, which retains the aesthetic appeal of lead glass without its toxicity.
This evolution in the composition of crystal glass maintains its luminous qualities while adhering to modern safety standards.
Lead has been used in the making of some glass since The Egyptian Bronze Age. The addition of lead oxide to silicon dioxide (silica sand) made the molten glass softer, more workable; it flowed easier at a lower temperature and allowed the glassmaker more time.
The lead made the glass denser, heavier, clearer, and brilliant form of glass with fewer impurities and higher refractive qualities.
In Europe, lead glass artifacts with varying amounts of lead have dated to the tenth century; some are as much ⅔ lead to ⅓ silica/sand.
Before 1969 lead crystal was assumed to have a 36% amount of lead, and then lead levels dropped to 24% after concern grew of lead poisoning.
Lead Crystal must contain 24% lead to be considered lead crystal; more than 30% lead is known as Full Lead Crystal.
Glass with 10% or more lead is considered “Fine glass.”
In manufacturing lead crystal, sand (silica), soda ash, limestone, and lead are used in the recipe, resulting in a high refractive index.
Lead-free crystal glass is produced using the same ingredients as above, but the lead is substituted with titanium oxide and may include zinc oxide and or potassium oxide.
Titanium oxide imparts luster and increases the refractive index in the glass without having to add lead.
Zinc oxide is added as a flux which reduces the melting temperature.
Potassium can increase the refractive quality and clarity of crystal glass.
Toxic metals such as cadmium (think red, yellow. and orange colors,) chromium(green,) and lead concentrations have been found in the enamels applied to decorated glassware and wine and beer bottles.
Tests have shown that decorated glassware in The United States for young children contained dangerous amounts of toxins and far exceeded acceptable federal levels; flakes of paint from the outside of the glassware have been shown to come off the glassware in everyday use.
Learn more about lead from the Environmental Protection Agency by clicking here EPA
With Inert and impermeable qualities, soda glass contains about 70% silica, 15% sodium oxide (soda ash), and 9% lime with smaller amounts of ingredients, making up about 90% of the type of glass in use today.
Soda-lime glass is used in the glass industry to make everything from windows, bottles, and Ball Mason jars to most contemporary glassware and glass food storage.
I’ve written another article titled:
This article gives a more in-depth look at the different glassware such as borosilicate glass, and tempered and non-tempered soda-lime glass products we use in our homes.
In summary, while the traditional “ping” test and weight comparison may provide initial clues, they are not foolproof methods for detecting lead in glassware.
The application of a more scientific approach, such as using a UV light or acquiring a test kit, can offer a stronger indication of lead presence.
It’s important to remember that while lead crystal offers a distinctive beauty and sound, its use should be mindful, particularly with items that come into contact with food and beverages. If you enjoy the elegance of leaded glassware, do so responsibly, reserving it for special occasions and not for everyday use.
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