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What Is the Difference Between Crystal and Glass?

The difference between crystal and glass is based on lead content, though standards vary depending on geography.
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Defining the difference between crystal and glass is not an exact process. While is it true that all crystal is also glass, only certain types can be properly identified with this term. Outside this rather broad statement, however, there are not any ironclad rules that are universally invoked as part of the defining process. Across the globe, there are different standards that are employed in various countries around the world that determine if the quality and lead content of a particular substance can be properly classified as crystal or not. Even within some countries, the qualities that must be present in order for glass to earn the other name may vary.

The lead content of glass is usually a determinant in the classification of finished goods. In the European community, items that have more than 4% but less than 10% of lead monoxide usually earn the designation of glass. While this is not always the case, items that are found to have a lead content of 8 to 10% is granted the status of lead glass. Goods with a lead monoxide content of between 10% and 30% earn the designation of crystal. In the event that the lead monoxide content exceeds 30%, the item is often identified as lead crystal.

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In the United States, a lead monoxide content of 1% is sufficient for an item to be classified as crystal. In other countries around the world that do not adhere strictly to the standards used by the European community, the range of lead content required before glass can be identified with this term may range from anywhere between 3% to 15%. Items with a higher lead monoxide content would be classified as lead crystal.

Both, when molten, can be used to create beautiful and somewhat fragile pieces. Among the items constructed in this way are holiday ornaments, decorative figurines, delicate picture frames, and other items that are crafted with a great deal of detail. Crystal in all forms is considered to be especially desirable when it comes to dishware and drinking wear, as well as carefully crafted flower vases.

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anon958613
Post 9

Crystal glass and a crystal are two different things. A crystal is a solid with ordered atoms while crystal glass is still an amorphous type of glass. Although crystal is often times used as synonymous for crystal glass in common parlance, I think it is important that a distinction is made.

anon931527
Post 7

Crystal has a pretty chime when lightly tapped and a rainbow effect when held up to the light. l lived in stores as a child and I would go around tapping and checking for the rainbow. It should be at least 24 percent lead as established in 1965. I believe as originally stated by the EU, Royal Dalton is still a maker of crystal. People say that it takes a trained eye to know the difference without a technical degree. I never knew that. I thought it was like gold; it has different markers. I hope this helps.

zigzag333
Post 6

How can I tell if something is glass or crystal, without any maker marks, receipts, tags, or anything else that might have this information? Is it possible to determine which it is without looking through a microscope or taking it to an expert?

I have a theory. I was cleaning a decanter and wine glasses the other day and when my wet finger rubbed around the edge of one of the glasses, it made such a beautiful sound. This made me think it was crystal. However, I don't know if glass will do the same thing when rubbed with a wet finger, I haven't got any long stem regular glasses to compare them to.

Can anyone tell me if this "sound test" is just a myth, or if this is a good sign that it's actual crystal?

I have looked through guides about this and some attributes make me think it's crystal and some make me think otherwise. Example; The glasses do make a "ping" sound instead of a "thud" when the edge is tapped. I can hold them up to light and don't see a green, yellow, or gray hue to them, but at the same time I do not see any prism effect or brilliant colors shining through either. The edges don't feel sharp as the guides say glass would feel, nor does the etching. They are thinner than most regular glasses I've seen but they don't seem to weigh more than expected as would lead crystal.

I'm just not sure about how to tell! Does anyone have any input on this? Help!

anon127633
Post 4

Defining the difference between crystal and glass is an exact process. Crystal has the atoms/molecules arranged in a precise geometric arrangement, while in glass the molecules are random.

It was discovered by adding lead compounds to glass the refractive index would increase and so it would 'sparkle' like crystal (not quite as much as diamond, the crystal with the highest refractive index, and the best 'sparkle') Decanters: Look very closely into the decanter. If you see faint facets it's crystal. If clear or with small bubbles it's glass. 90 percent will be glass.

anon86334
Post 3

buy a lead testing kit. they are cheap and you can buy them at hardware stores.

mdt
Post 2

Your best bet is to take them to someone who can examine them closely and determine if there is any lead crystal contained within the glass mixture. A local jewelry store that also carries crystal items should be able to point you to a local expert that can help you.

gdmoseley
Post 1

How can I tell if the cut glass decanters I purchased second hand are lead crystal. I want to know in relation to the safety of using them to store liquors and other spirits such as flavored rums.

I know that you are not to store acidic beverages such as wine.. .

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