Identifying Fake Sea Glass
By Mary T. McCarthy
Real, natural sea glass or beach glass comes from an ocean, lake, river, or sea. The North American Sea Glass Association, whose mission is to educate collectors and consumers about genuine sea glass, requires its members use only real sea glass, “not altered by acid etching, sand blasting, tumbling, or by any other means so as to artificially replicate genuine sea glass.” This gives us a rough definition of fake sea glass: anything that’s manufactured to replicate genuine sea or beach glass.
It’s often a challenge—even for a seasoned collector—to tell the difference between real and fake sea glass, and unfortunately, many people spend lots of money buying imitations.
Several terms are used by manufacturers who are not trying to pass off their product as genuine sea glass. Products labeled “Eco-friendly glass,” “recycled glass,” “green glass,” and “cultured glass” are just a few terms used by businesses who create products that resemble, but are not, genuine sea glass. Another term is “twice-tumbled,” which refers to beach-found glass that has been placed into rock tumblers or cement mixers to finish and smooth the edges.
Ideally, these products are labeled appropriately, so buyers know that what they’re purchasing is not real sea glass. Unfortunately, this is not always the case. In fact, one of the largest manufacturers of imitation sea glass labels all their jewelry as “SEA GLASS.”
The number of artificial sea glass manufacturers has grown as demand for genuine sea glass has increased and supply has decreased. A large percentage of online sea glass sold on eBay and Etsy is not genuine beach glass but is instead created to look like sea glass.
5 Tips for Identifying Fake Sea Glass
Buyers often cannot tell the difference between real and fake sea and beach glass, either in person or online. Here are five things to look for before you buy or trade.
1. Best. Beachcomber. Ever.
Does the person keep selling similar batches of the same rare styles and colors and shapes of glass over long periods of time with hundreds of sales? No beach in the world produces endless pounds of rare colors in perfect, jewelry-quality shapes and sizes. Positive reviews on eBay and Etsy are not a reliable way to determine trustworthiness of sellers, since people have been buying fake glass—often without knowing it—for a long time.
2. Stranger danger
Did the seller find the glass themselves? If not, they may have purchased fake sea glass, even unknowingly, that they are selling as real. The best way to know you are buying genuine glass is to buy directly from beachcombers. Often someone on Facebook or Instagram can recommend beachcombers that sell their finds.
3. Smooth operator
Tumbled glass generally is unusually smooth compared to genuine sea glass. There is sometimes a powdery sheen on tumbled glass that is not present on wave-worn glass. There are some exceptions where certain beach or lake locations create “silky” glass, but using an inexpensive jeweler’s loupe to magnify the glass, you can see internal stress and hydration marks throughout a genuine piece of sea or beach glass. Fake pieces will show marks only on the outside—or no marks at all.
4. Stay frosty
Although long touted as the mark of genuine sea glass, “C” marks are not a reliable way to tell the difference between genuine and artificial glass, as they can appear on both wave-worn and acid-washed or tumbled glass. Real hydration over time in a natural body of water leaves a more random pattern of C marks, and wears the piece of glass in a less uniform way. Look for asymmetrical overall shapes and unevenly distributed markings in real glass.
5. Unbelievably good
If it looks too good to be true, it probably is. Perfect glass at a super-low price is a tip-off that the glass may not be real. Or, a rare color or unique shape found on an otherwise average beach may have been “seeded” by someone.
P.S. A final word
There is a lot of concern about real versus fake, and many people ask me to identify their pieces and determine if they are genuine. I feel the pain of those who have bought or traded for fake glass, trust me. If you didn’t find it yourself, you can’t be sure. But perhaps we shouldn’t worry about the origin of a piece of glass as much as whether we find beauty in it. If you bought something and you like it, you can decide if it matters whether it’s genuine or not. Should people buy, sell, or trade sea glass they aren’t 100% sure is real? Absolutely not. But I hate to see the joy of beach finds tarnished by discussions of whether they are real or fake. I’d much rather ask, “When’s low tide?”
Watch the video below by Mary McCarthy to see great examples of genuine versus artificial sea glass, and to learn more about how to tell the difference by shape, color, and surface textures. She shows examples of tumbled, manufactured, and real sea glass, side by side.
Learn more about Mary McCarthy ›
This article appeared in the Beachcombing Magazine January/February 2019 issue.