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Sea Glass, Beach Glass, Tumbled Glass
What's the Difference?

sea glass
A stack of beautiful blue and green "sea glass" that was naturally tumbled in the ocean by wave or current action. Notice how its surface has a "frosted glass" appearance and how the pieces have a curvature inherited from a glass container. The name "sea glass" is used for glass that has been naturally tumbled in the ocean. The name "beach glass" is used for glass that has been naturally tumbled along the shore of a lake or a river. These naturally tumbled glasses are desired by collectors and often used for jewelry or craft projects. They have inspired many people to use a rock tumbler to produce tumbled glass. Photo by Jodie Coston © iStockphoto.

"Sea Glass" and "Beach Glass"

Much of the interest in tumbling glass has been inspired by materials known as "sea glass" and "beach glass." These are naturally-tumbled glasses that can be found along ocean beaches, river banks and lake fronts in many parts of the world.

These pieces of glass might have once been part of a glass jar or bottle that was broken along the beach or dumped in an offshore trash disposal site. Wave or current action then picked up the glass and tumbled it along the bottom - with sand on the bottom serving as a natural abrasive. Over time that tumbling action rounded the pieces of glass, smoothed their surfaces and gave them a frosted finish.

What Each Name Implies

Naturally-tumbled glass found at an ocean is called "sea glass." When it is found along a lake or a river it is called "beach glass." The names "sea glass" and "beach glass" attribute a provenance to the glass and imply a naturally-tumbled material.

Lots of people have made a hobby out of searching for sea glass and beach glass and consider each piece that they find a treasure. They use attractive pieces of naturally-tumbled glass to make jewelry or other craft projects.

Sea Glass is Becoming Scarce

Sea glass is not easy to find today and it will become even harder to find in the future. It declines in abundance as plastic containers and recycling reduce the amount of glass that enters the beach environment. Landfills have also replaced ocean dumping as a disposal method for trash.

The problem with using naturally-tumbled glasses in craft projects is a reliable source of supply. This is what motivates many people to produce tumbled glass in a rock tumbler. Others are motivated by the bright gemmy appearance of highly polished glass.

Deceptive Sea Glass Sales

If you want a nice piece of "sea glass" because of its rarity and its interesting history, you might not get what you are paying for from some vendors. Much of the material in the market that is sold as "sea glass" is actually man-made glass that has been tumbled to a frosted finish in a rock tumbler or similar machine. The owner of the tourist shop at the beach might not even know that the sea glass for sale in his display case is fake.

If you are a seller of "sea glass" produced in a rock tumbler, the name that you are using to market your product is incorrect. Furthermore, depending upon your intent and the perception of your customers, the practice that you are engaged in could be considered as misleading, or deceptive, or fraudulent, or criminal.

Tumbled glass is not rare. It is produced in large quantities in the United States, in China and in other countries. It lacks the interesting origin of genuine sea glass that many people value. Tumbled glass has no value beyond that of a common piece of glass that was tossed into a tumbler.

If the tumbled glass that you are selling is anything different in the buyer's mind than a man-made bauble - and you have called it "sea glass" to stimulate sales - you could face a civil suit from your customers or a criminal suit from the United States government. Lots of tumbled glass is being called "sea glass" and lots of buyers and some sellers don't know the difference. Most can't tell them apart.

We are not attorneys and we don't give legal advice. We are simply providing friendly caution to interested people.
Kauai Hawaii Sea Glass Beach
Photo of sand from a beach on Kauai, Hawaii that contains significant amounts of naturally tumbled glass in a variety of colors. Photo by Ann Marie Kurtz © iStockphoto.
sea glass and rocks at Glass Beach, near Ft. Bragg in Northern California
Photo of sea glass and rocks at Glass Beach, near Ft. Bragg in Northern California. Photo by Julie Vader © iStockphoto.
sea glass
Sea glass in a variety of colors - green, amber, clear, cobalt. Photo by Susanne Friedrich © iStockphoto.
blue sea glass
A beautiful collection of sea glass in frosted shades of beautiful cobalt blue and white. Photo by Eileen Hart © iStockphoto.
sea glass
An antique canning jar made of a beautiful shade of blue glass that holds and displays a sea glass treasure. This is one of our favorite photos. :-) Photo by Todd Bates © iStockphoto.
sea glass
Sea glass found on the beaches of Half Moon Bay, California. Photo by David Wilkins © iStockphoto.

frosted sea glass
A cache of sea glass with the frosted ocean patina. Photo by Joe Potato Photo © iStockphoto. Authors

Hobart King Hobart M. King has decades of rock tumbling experience and writes most of the articles on He has a PhD in geology and is a GIA graduate gemologist. He also writes the articles about rocks, minerals and gems on