Sea Marbles: Holy Grail of the Beach

chesapeake bay beach glass marbles

By Mary T. McCarthy

For sea glass hunters, there are few finds as exciting as the discovery of that perfectly round orb among the gravel, or the flash of color in the water (perfume stoppers and a few other bucket list finds excepted). Finding a sea marble brings inevitable joy, and to those who have not found one yet, perpetual frustration: “when will I finally find a sea marble?”

In 2017, I had the opportunity to lecture on “Sea Marbles Around the Globe” after developing a collection of marbles from two dozen beaches around the world, talking to beachcombers from many different countries, studying the history and manufacture of marbles, interviewing marble experts, and visiting the National Marble Museum in West Virginia. It was a fascinating journey, and I learned a lot during these talks, even about two types of marbles I never knew existed (steamship marbles and railroad marbles).

red swirl sea glass marble

Marble History

To understand how marbles end up on the beach, you have to understand a little bit about marble history in general. Marbles date back to 3000 B.C. in Roman, Greek, and Egyptian history. Did you know David took down Goliath with a marble in his slingshot? The earliest North American marbles were found in ancient earthen mounds. Handmade (clay, agate, and other stone) marbles from Germany date to around 1850-1900. Elias Grenier patented the first marble making scissors in 1849. In 1870 Hiram Codd created Codd soda bottles in England to preserve carbonation.

In the United States, by the late 1800s, clay marbles were being produced in the U.S. where glass marble manufacturing began in the 1890s in Ohio. M.F. Christensen patented the first marble-making machine, but Akro Agate was the biggest; their slogan was “Shoot straight as A Kro flies.” Marble tournaments began way back in 1588 at Tinsley Green in England to win the hand of the milk maiden Joan; that tournament continues today. In the U.S., marble tournaments began in 1922 in Wildwood, New Jersey (for boys; girls weren’t allowed to compete until 1948) and were a huge competitive hobby. Because of all this early marble activity, the Great Lakes and New Jersey beaches are still popular places to find sea marbles today.

beach glass bonfire marbles

When the cat’s eye marble was invented in Japan around 1945, there were over three dozen marble manufacturers in the U.S. and most of them closed because the kids wanted the new style of marble. Only one American marble company remains today. Founded by Berry Pink and Sellers Peltier in 1949, Marble King in Paden City, West Virginia still produces one million marbles a day, seven days a week, 365 days a year. After sneaking over to Japan to discover the design process, they produced the first standard American cat’s-eye marble (though technically Peltier had a similar earlier design in the 30s). They’ve sponsored the National Marble Tournament since 1968.

mary mccarthy first sea glass find

Beach Marbles

The marble in the photo above is the very first piece of sea glass I ever found. When we first moved to the Chesapeake Bay area nearly two decades ago, I looked online and found a nearby beach park and took my kids. It turned out the spot used to be an old amusement pier a century ago. I was walking along the shoreline while my kids played, and I looked down and saw the perfectly frosted orange cat-eye marble. I picked it up, turning it over in my hand, not really knowing at the time that it was sea glass, or even knowing what sea glass was (having grown up landlocked). I kept it, noticing there were other pieces of frosty-looking glass on the beach. One day in a local shop I stumbled across a book about sea glass (Pure Sea Glass by Richard LaMotte) and picked it up, noticing the section about sea marbles. I was hooked, and have been an avid beachcomber ever since.

It turns out in the big scheme of beachcombing, finding sea marbles is actually very rare. Finding one of the holy grails as my first piece was a blessing and a curse. It set an impossibly high standard.

sea marbles

How Do They Get on the Beach?

It’s been said that ship ballast is where marbles come from, and although I haven’t found primary documentary evidence for this, it’s not impossible, but not a probable common source. For one thing, childrens’ playing marbles, the most commonly found beach marble, were generally produced in the 30s-60s and beyond (and American marbles were generally transported by railroad), so not generally the timeframe of ships. If there was a type of marble that would have been used as ballast it would perhaps have been an inexpensively made, older and mass-produced marble, older even than a glass marble. Is it possible that clay marbles were used as ship ballast? Anything’s possible, though most ballast consisted of cheap, locally available rocks and stones, which could be dumped when a ship needed to enter a harbor. Read more about why marbles were almost certainly not used as ships ballast in Myth: Glass Marbles were used as ships ballast.

Although playing marbles may not have been used as ballast, they were definitely being transported by ship between Japan and the U.S. and could have been lost through shipwrecks or cargo spills. Usually, only the lightest items such as plastic toys and lightweight equipment wash up on beaches, so the marbles did not likely come from shipwrecks.

There’s a type of white clay marble found in different sizes around the world that was used for a very specific purpose. Brought to me by a diver at a sea glass festival, he claimed his collection was of a type of “steamship marble” that had been collected over the years. A steamship captain explained to him that is was forced through different sizes of pipes to clear out the salt build-up. This use has not yet been confirmed.

Another type of industrial marble found regionally is a “railroad marble” or "industrial marble." These marbles are larger than a playing marble, are identified by a rough seam line from where their two halves were crudely placed together in the manufacturing process, and they’re found along creeks, rivers and lakes that are connected in some way to railroad lines in the U.S. They were used in the production of fiberglass, a huge industry in the Great Lakes region beginning in the 20th century.

Codd marbles were invented in the 1870s to keep carbonation in drinks. They are found on beaches, more in Europe than the U.S. since that’s where Codd bottles were manufactured, but bottles from London made their way, primarily to the Northeast, where they’re sometimes found. Japanese Ramune bottles also use a marble to maintain the carbonation of the sodas they contain. 

They’re a less common find than playing marbles. Children playing on beaches with marbles (slingshotting them, as Mary Beth Beuke points out in her book The Ultimate Guide To Sea Glass) is one reason they are there now. Another very common reason marbles are on the beach is trash dump erosion. Parents threw out their children's discarded toys and the garbage tip eroded into the water.

marbles from vintage reflective stop signs

Other marble sources besides play marbles include their use in reflector lights, household objects like broom handles, furniture feet, ballot boxes, jewelry dish and lamp décor, paint cans, and doll and stuffed animal eyes.

how to find sea glass marbles

How To Find Them

Think like a marble. Though it seems obvious, you have to go where the marbles are. They have to come from somewhere. Check out beaches near ports or shipping channels, or on beaches like old resorts where lots of children played. Beaches near where trash dumps were located are ideal for finding marbles. Marbles don’t like to wash up on sand, they prefer rolling around in rocky areas. They don’t roll uphill obviously, so they will often be found just below the tide line and therefore can more often be found in a negative low tide. Always check tide charts: winter can often be the best season to find marbles. Marbles are a toy, like to play hide and seek, so be patient in your search.


Marble Mania by Stanley Block, Schiffer Publishing, 2011 is a great resource for information and history on marbles, and online you can check out for a wealth of information about vintage marbles.

This article appeared in the Glassing Magazine November 2017 issue. The article was updated by Beachcombing staff in 2023.

Learn more about marbles

magazine articles about sea marbles found on the beach

Learn more about the different types of marbles you can find on the beach and where they come from. Articles ›

Learn more about beach-found toys and games

toys and game pieces found on the beach

Learn more about marbles, dominos, dice, toy vehicles, and more found on  beaches around the world. Articles ›

Marbles aren't the only toys found on the beach. Check out these Beach-found toys and games from around the world 


David took down Goliath with a stone and not a marble.

jean April 01, 2024

Translation of Christiaan’s comment:
5 years ago I came into contact with a man who went along with such a truck that was going to empty the sewer drains everywhere. Once the tank was full, they were then allowed to pour the contents onto farmers’ land. Huj then had to pull the contents onto the land. He could keep whatever he found. He found kitchen knives, coins, paper money, and … marbles. He already had thousands of them and I could buy them for next to nothing. I still have these. I live in Roeselare (Belgium).

My response: That is so cool! It would be great to see some photos of your collection! You can email them to Thanks for the fun story!

Dat is zo gaaf! Het zou leuk zijn om wat foto’s van je collectie te zien! U kunt ze e-mailen naar Bedankt voor het leuke verhaal!

Kirsti August 27, 2023

45 jaar geleden kwam ik in contact met een man die meeging met een zo’n camion die overal de rioolputjes ging leegzuigen. Eens de tank vol was, mochten ze dan de inhoud bij boeren op het land uitstorten.Huj moest dan de inhoud optrekken op het land. Alles wat hij dan vond mocht hij houden. Zo vond hij keukenmessen, munten, papiergeld, en …knikkers. Hij had er reeds duizenden en ik kon die voor een prikje kopen. Ik heb deze nog altijd. Ik woon in Roeselare ( België).

Christiaan Therry August 27, 2023

Hi, Nicole! It could be a marble that was broken so there’s a flat side and a round side!

Kirsti Scott November 22, 2022

Hello and thank you very much for helping me figure out what this is. I’m obsessed with sea glass and have been hunting for about a decade and finally found this to me gem lol but is it a sea glass marble or just sea glass? It’s flat on the bottom

Nicole Frey November 22, 2022

found a aqua blue marble size piece of what i think is crystal in NS today as well ,, Wonder why these are all washing up in NS

c crane May 24, 2022

How can I get in touch with the author, Mary T. McCarthy? She mentions a beach that I believe I’ve been to in Kent County, MD

Jackie Medford January 20, 2022

Yesterday I found 8 marbles during my weekly sea glass hunt. They were cats eye marbles of the type that are sold in bags at a toy store. I’ve been hunting sea glass for a while now and had never found a marble before, then 8 in one day.

MHL January 06, 2022

I am a collector of marbles, among other oddities, and I love beachcombing. There are not a lot of beaches more than a four hour drive from where I live, however, so I have taken to digging for marbles. I have found… more than I expected. Do you have an explanation as to why there are marbles in the ground? I would not think that people would just throw these toys away.

Felix March 11, 2021

On 1/23, just days ago, at Shasta lake in N. CA, the lake is a resovour and is right now down 75’ or so, that leaves miles of shoreline to explore and the Sac. river flows now where lake once was untill it fills again, the rocks here are beautiful in color and while walking in the sacramento river I found a round , more like egg shape, glass “we call it the marble” its awesome, as big as a large marble. We compaired it to some insulators the aqua blue ones and belive that is what it was at one time its frosted but you can see some air bubbles in it. I have found some cool things here at the lake, but this is the once in a lifetime find for me.

Mark collier February 11, 2021

I have found a beach quiet beach and have found glass balls almost every time I visit this beach on Lake Ontario . It’s at a mouth of a river and close to a railroad tracks.
I nick named it Glass Ball Beach…
I have never found them anywhere else .
Can you explain what they are and from where they may have originated.

Gary Hutchinson February 11, 2021

I have a bag of sea marbles gifted to me years ago from a woman who collected them when her grandfather would take her on boat trips out to Boston Harbor Islands I think in the 30’s . She told me a few of the larger ones that look like stone were ship ballast. I can not confirm.

mary cooney January 18, 2021

I saw one video where a glasser speculated that some of them might come from small children flushing them down the toilet by the hundreds, in the days when sewage went directly into the ocean. He said the hypothesis seemed a lot more plausible after he had kids himself. In a town of several thousand or more with a sewage pipe to the sea, just a tiny portion of the kids flushing marbles could end up putting thousands of marbles into the ocean to tumble around.

Sam Dunford January 18, 2021

I live on the Eastern shore outside of sheet Harbour, NS and I also found a blue marble yesterday .

Megan November 13, 2020

Can’t figure out the origin of this “marble”.

Rod Gillis August 24, 2020

Three weeks ago I found a blue marble piece of sea glass beside some seaweed on a beach in Glace Bay, NS. It wasn’t perfectly round but definitely a marble. I have no idea of its origin but it was about 5/8" in diameter. I doubt it came from a bottle because it was too thick, even for the bottom of a bottle.

Rod Gillis August 24, 2020

Leave a comment

All comments are moderated before being published