What is Sea Glass?

If there’s a heaven for me, I’m sure it has a beach attached to it. 

~ Jimmy Buffet

Loose Sea Glass in Various Colors
Typical Seaham Sea Glass
blue multi-colors sea glass
Multi-colored Sea Glass from Seaham Beach
sea glass from France
Low Grade Sea Glass on the French Riviera
Vintage sea glass pestle
Vintage Glass Pestle Found in Spain

So what exactly is sea glass and how is it made?

Sea Glass, sometimes referred to as Beach Glass, is unique in that it has been naturally tumbled by the sea and sand for years. Artificially tumbled glass is not the same thing and should never be referred to as “Sea Glass.” Our genuine sea glass has been found by us on the beaches of Florida, Mallorca, England, Barcelona, and the French Riviera. Some of the oldest pieces of glass we have (called black glass), were found in the water off of the island of Mallorca, Spain. The other tell-tale sign that separates authentic sea glass from tumbled glass, is the frosted appearance and the visible “C’s” covering the outside. For some reason sea glass that comes from the ocean has many C shapes carved into it from the salt water and rocks. That is impossible to achieve by tumbling the glass. Most tumbled glass has a smoother more uniform look. 

Sea Glass is categorized into “grades”. It is split between Jewelry Quality (JQ) and Craft Quality. They are then split into Grade A and Grade B. If you are buying sea glass online, this is an important distinction. Low grade sea glass is usually more flat and has rough or jagged edges. The best sea glass will be rounded and have very smooth edges. This means that it is older as well. There are several factors that contribute to its grading. You can learn more on our Sea Glass Quality page.

Much of the best sea glass is found on beaches where glass factories used to be located, such as in Seaham, England. Seaham is famous for it’s sea glass because it is roughly 100 years old and most pieces have a beautiful rounded, frosty quality. The other unique aspect to glass factory glass, is that it tends to be more colorful. Now, that doesn’t mean you won’t find clear, greens and browns, but even they will tend to be rounder and better quality than “trash glass.” At the end of each work day, all the left over glass from various bottles, and decorative items, was pushed off the cliff into the sea. There is sat being tumbled by salt water and rocks for a hundred years, then washed back up with the tides. You can find especially good glass after a big storm, when all the oldest glass sitting on the bottom is stirred up and washes ashore. 

The sea glass at Seaham Beach is getting more scarce, however. With the advent of the internet, word spread about the unique and stunning sea glass on Seaham Beach and sea glass hunters and enthusiasts from around the world began to travel there with the express purpose of going sea glass hunting. 

You can now see dozens of people from dawn until dusk scouring the beach at low tide. There are still some treasures to be found there, but it is unpredictable and planning travel around sea glass hunting is risky. We went in the fall of 2019 for the second time and it was not good. We stayed for about a week before packing up and heading to Spain instead.

Understanding the value of sea glass will better help you to sell the loose glass and sea glass jewelry. The loose glass that I sell to jewelers pays for all my travel to Europe, to gather more glass. If your goal is to search for fun or decorate your house, then there are many beaches in Europe that you can find that kind of sea glass.

How old is sea glass?

The age of sea glass is difficult to estimate. It takes approximately 20-50 years to achieve the frosted appearance and the more time the glass spends in the ocean, the more rounded and smooth the edges get. A good rule of thumb is that generally, the thicker the glass and the more rounded the edges, the older it is. Glass products are made much thinner today, than they were a hundred years ago. The oldest pieces in our collection is the “black glass” found off the coast of Spain. These are much thicker than the others and usually have a slight tinge of olive green when held up to the light. They are absolutely stunning in the sunlight. They are estimated to be from 200-2000 years old! The oldest coming from the Roman Empire. Many also came from old ships in the Mediterranean.

Sea glass in hands
Corla on the beach
Les Issembres, Côte d'Azur
Seaham Beach
Seaham Beach
Sea Glass on Seaham Beach
Seaham Beach