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How is Sea Glass Made?

Marooned on an island, he throws a bottle into the ocean...in
time, it winds up broken on a rocky shore, the note lost forever... 

It is exciting to think that the glass you have found on the beach may have arrived after an exotic journey floating on the ocean currents.

Imagining such a romantic origin of your sea glass is lots of fun, but it is more likely that your beach gem had a much more commonplace beginning.

Follow along as we look into a more probable source of that rounded and frosted shard of prized sea glass.

On this page:

  1. The Source of Glass - Trash
  2. Recycled Glass Bottles
  3. Colored Glass Bottles
  4. Imagination - The Unkown

See Also:

  1. The History of Glass

Trash Dumps as the Source of Beautiful Sea Glass

The nicely-tumbled glass with the frosted but glowing colors that we easily recognize as sea or beach glass likely came from a much more humble source - the trash dump.

Since glass is the longest lasting item in an old trash dump (doesn't rust or decompose), most of the sea glass begins its life as old glass bottles, including those beautiful colored glass bottles, and then it ends up right where it should be - on the beach, where it takes on a new life as recycled glass bottles, that is, beach glass (including lake glass or sea glass).

How is Sea Glass Made - Old Glass Bottles

The origin of sea glass began with what was once bottles, jars, glassware, dinnerware, et cetera.

It usually ended up in bodies of water or on the beach as garbage. Large trash dumps long ago produced the best glass beaches. There are a number of other less likely possibilities, for example shipwrecks near the shore.

For home dwellers that lived close by the sea or lakes in times past, the shore was as good a place as any to get rid of their refuse.

Years ago, people weren't too concerned about the environment, so a lot of junk and garbage was dumped into the oceans and lakes.   

We've written a lot more about this main source of sea glass on our page Finding Sea Glass.

Glass does wind up on beaches in other ways discussed below, but all the major "glass beaches" have an old trash dump as their source. 

Another way that the "raw material " for beach glass finds its way to the beach is from boats.

Trash, believe it or not, is still regularly dumped into ocean waters from many large and small seagoing vessels.

Just like in the old stories of someone marooned on an island who puts a note in a bottle and throws it out in the current and someone on the other side of the world finds it, corked bottles will float a long way.

Amazingly, uncorked bottles can float long distances also. These bottles may find their way to the beach, where they are busted up when the waves hit the rocks or other objects.

However, sea glass from floating bottles will only form an extremely small percentage of the glass you'll find on a beach.

Glass floats are still being used in fishing nets. Nets get old and torn. The glass floats come loose.

Some of the more unusual colors you might find may come from these floats. 

Recycled Glass Bottles

Glass found along shipping lanes can often come from sailors throwing bottles into the sea (no longer done, of course!).

There are also interesting pieces of glass from oriental fishing floats that have broken up on the beach.

How is sea glass made...The shards from these various sources have been tumbling around in the water, sometimes for decades, before finding their way onto a given beach at a given time.

Over time, nature takes what was once man's garbage and turns it into sparkling natural gems - naturally recycled glass.

This process is the result of wave action tumbling the shards among rocks and sand between the tide lines.

Tides, in a twice a day cycle, cover and uncover that glass, exposing all sides to sunlight and, with the passage of time, some of the components of the glass are leached by the water around it, resulting in that frosted look that identifies genuine tumbled sea glass.

The amount of wave action directly affects how quickly a shard will become real sea glass. Sea glass/seaglass shards could take from 5-50 or more years to become that true object of natural art and beauty that we so love.

Click here for detailed description of the factors involved.

When life’s a beach . . . get crafty! Coastal Crafts carries you straight to the shore, with projects that incorporate seashells, ropes, sea glass, and a range of nautical materials and motifs. 

Learn how to weather surfaces, make driftwood, and cast sand. With everything from wood frames and hanging jars to decorative sailboats and a knotted necklace with shells and pearls, these beautiful items celebrate summer all year long.

Colored Glass Bottles

  The results delight the eyes and emotions of people of all ages, young and not so young.

We have met people on the beach who've been collecting sea glass for over 30 years.

There's something so alluring about walking on the shore and finding a piece of sea glass.

For some, collecting sea glass is closely tied up with fond memories of childhood, family visits to the beaches, solitary walks alone.

For others, it's trying to figure out where the sea glass came from - what's the history of that particular piece of sea glass - how old is it. For them, that's half the fun of it.

Imagination - The Mystery of How is Sea Glass Made

 No matter how you much you can guess at, in most cases you'll never really know where your piece of beach glass came from - or exactly what it went through to become what it is now.

On the other hand, we do know that there are a number of factors that must be present to turn a glass shard, no matter where it came from, into a beautifully-rounded and frosted piece of sea glass.

Those factors or conditions that are needed to produce the best sea glass are explained in this topic Finding Sea Glass - Meeting the Conditions.

Even with the best conditions, it's kind of like solving a mystery - how is sea glass made, how'd this particular piece come to be what it is. Imagining. It's something we never get tired of doing.

What we find today is what keeps us going back tomorrow.

Next >>> What Makes the Different Colors?


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Red Sea Glass from Russia

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Browse Our List of Recommended Sea Glass and Beach Books

Note: Sea glass usually refers to naturally tumbled glass that's found on saltwater shores, while beachglass or beach glass can refer to the tumbled glass found on any body of water with enough wave action, such as large lakes.

Lake glass is a term not used very often but is accurate if used for beach glass found on the large lakes such as the Great Lakes of North America.    

Where to find sea glass

US sea glass reports beaches


Beach Glass - naturally wave-tumbled and frosted glass found on fresh-water or salt-water beaches.

Sea Glass - beach glass found specifically on salt-water beaches

On What is Sea Glass