Home - What is Sea Glass

What is Sea Glass and/or Beach Glass?

When you are first starting to collect beach glass or sea glass, you might have questions about what you've found.

Even those with more experience might have trouble telling if a certain object is beach glass or not.

We'll answer the main questions - What is Sea Glass? and also the related question What is the difference between Beach Glass and Sea Glass?

What is Sea Glass?

And...does any piece of glass found on a beach qualify as beach glass or sea glass?

Here are the most important factors that give beach glass its characteristic etched and glowing appearance.

These four marks of identification will be present for a shard of glass to meet the classification of beach glass or sea glass:

  1. It is glass that has been discarded and ends up on a beach.
  2. Wave action on a sandy or rocky shore tumbles, rounds, and etches the glass.
  3. Sunlight reacts with elements in the glass, contributing to an etched surface and sometimes a change in color.
  4. Chemical composition of the water also dissolves (leaches out) certain substances of the glass, contributing to very tiny pitting or etching of the surface of the glass.

When a glass shard has been naturally tumbled, rounded, and etched on all surfaces, it is classified as beach glass.


  • Beach glass - is found on freshwater or saltwater beaches
  • Sea glass - found only on saltwater beaches

What is Sea Glass

Is it Sea Glass or Beach Glass?

Sea glass is beach glass - beach glass is found on freshwater or saltwater shores, but sea glass is found only on saltwater shores.

Beach glass and sea glass are shards (pieces of glass) that shows specific characteristics. We'll talk about those characteristics next.

For simplicity's sake and because of its common use, we will sometimes use the term "sea glass" to refer to both fresh and saltwater beach glass.

What is Sea Glass

More information on the difference between beach glass and sea glass:

The more general term "beach glass" refers to glass that can be found on fresh or saltwater shores, but "sea glass" is beach glass specifically found only on saltwater beaches.

  • The differences between freshwater beach glass and saltwater (sea) glass are so slight that in many cases no real differences are noticeable.
  • However, most freshwater lakes lack enough wave action to tumble the glass. That and the fact that there are so many more miles of saltwater beaches in the world means that most of the beach glass that you will see is from ocean beaches. For that reason, the term "sea glass" is more commonly used.
  • Usually, if a piece of beach glass has been found on a lake, that fact will be mentioned.


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Since most of the beach glass found is from saltwater shores, the term sea glass is used generally to apply to all glass shards that have the necessary characteristics (marks of identification).

What is Sea Glass 

Is the piece you've found sea glass?

It is beach glass if:

  • It was naturally tumbled by wave action on a beach.
  • All surfaces are etched - there are no shiny surfaces.
  • There are no sharp edges (the exception would be beach glass that has later been broken, leaving a sharp edge).
  • Then, if you found it on a saltwater beach, your beach glass is more specifically called sea glass.

What is Sea Glass

How can you tell if what you have found is beach glass (sea glass) or just a pebble?

Even for experienced sea-glassers, it is at times hard to tell the difference between certain pebbles and sea glass.

How to tell:

First, it must show the characteristics or marks of identification mentioned above.

  • Hold it in front of a bright light
  • If it's sea glass, you will see light coming through evenly with little or no lines, spots, cracks, or layers*
  • Wet the object thoroughly. There will be a big difference in color, and you will be able to see more light through the glass evenly (if it is very dark, of course, you might not see through it; however, it will be noticeably clear).

*There are exceptions to the above instructions; for example, fire melt (bonfire glass) and semi-opaque glass such as milk glass, jadite, insulators, some marbles, ceramics and other semi-transparent glass are not clear. 

These steps, however, will eliminate most rocks or pebbles that look like glass.

sea glass colors line

Definition -

Glass Becomes Sea Glass or Beach Glass when:

1- A piece of glass has been tumbled by natural wave action to the point where there are no sharply-defined edges or corners, and

2 -The natural action of elements in the water along with sunlight and tumbling action have produced a unique frosted or etched surface covering all sides of the glass.

If these two factors are not present, it is just a glass shard, no matter where it is found.

*The term "Beach Glass" is more general and includes naturally-tumbled glass that is found on freshwater beaches as well as ocean beaches.

sea glass colors line

What is Sea Glass? - People are Naturally Curious

~ comments by Lin

Usually, if someone is walking along a beach and sees me bending over, hands on knees, scrutinizing the sand and pebbles, they slow right down, and kind of try to see what I'm looking for. Then, if they aren't too inhibited they'll ask, "What ARE you looking for?"

What is sea glass?

So, I'll say, "Sea glass," and see how they respond. Some will ask right off, "What IS sea glass?" Some already know what it is. 

On the other hand, some are hesitant to let on that they don't know what sea glass is, so then I'll usually ask them if they know what sea glass is.

If they don't know what sea glass is, I'll say something like: 

"You know, when you're walking along the beach and you find little pieces of glass of different colors. 

Those are from busted up bottles and glassware that have been in the salt water for a long time and because of the currents and the sun and the waves and the sand, they turn out really frosty."

If I get a blank look as if to say, "Why in the world would you want to pick up broken glass?"

I'll usually show them pieces of frosted glass that we've found that day.

Or, if I'm wearing a piece of sea glass jewelry, I will show them that. 

Then, it's like, "Oh, wow!"

Lin Schneider
david and lin schneider

What is Sea Glass

Identifying Real Sea Glass

Have you heard that the best way to learn to identify counterfeit money is by getting very familiar with the way real money looks? 

The same is true of sea glass or beach glass.

One of the best ways to answer the question, "What is sea glass" is to see the real thing.  

The more you see, the easier it will be to recognize.

Get familiar with the look of genuine sea glass as seen in our photo galleries:


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