Marbles are often considered the cream of the crop among sea glass aficionados, right up there with bottle stoppers and antique game pieces like glass dice.  Without a doubt, they are a true treasure to find on the beach.  But how did they end up there?

There are a few theories floating around as to why marbles end up on the beach, tumbled and frosted by the waves:

1. Children often played classic marbles in the sand on the beach, and used marbles in sling shots to do target practice.

2. Codd-neck bottles and Ramune bottles both rely on marbles to seal their contents. The bottles are filled upside down, and the pressure of the gas in the bottle forces the marble to seal the top.

3.  It is said that ships would fill the keels of ships with marbles to ballast the ship in waves and storms.  These ships would occasionally shipwreck, sending the marbles into the sea.

4.  Japanese cat eye marbles became popular in the U.S. before they became available there.  They were often transported in ships, and occasionally shipwrecked, spilling their contents into the ocean.

5.  Clay steamship marbles were often used on ships to clean pipes from salt buildup.

6. When marbles were still widely manufactured in the U.S. (today there remains only one manufacturer), they were transported by railroad; sometimes derailing and overturning.  The marbles make their way into waterways and get carried to the sea.

7.  Painters would add marbles to paint cans to help mix the paint.  These cans would end up at the landfill, eroding and making their way into rivers - then to the ocean.

8.  Its been reported that railroads transported marbles to then be made into fiberglass.  They often have an imperfect look, with visible seams from manufacturing.

9.  Lastly, trash dump erosion is a big reason why all types of glass (and unfortunately garbage) end up in the ocean.  Old dumps were often near beaches, and eventually break down and end up in the ocean.

As I mentioned, these are all theories we can only speculate on.  How any marble ends up in the waves - to be perfectly tumbled frosted by mother nature - is anyone's best guess.  But that's part of the fun, to imagine the story of the sea glass before you found it.  Have you ever found a sea glass marble?  What's your favorite ever sea glass find?  Tell me in the comments.

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