What is Sea Glass?

Home / What is Sea Glass?



Natural surf-tumbled sea glass is fragments of glass that made their way into oceans, lakes, rivers, streams or other bodies of water where they were weathered and tossed around by the water against sand and stones until they found their way back to the shore years later in a new frosty and thicker gem-like form.

Real sea glass has never been changed or altered in anyway by people; however, some natural sea glass has been drilled by jewelers and artisans for practical reasons.

What is Sea Glass

sea glass



Most sea glass comes from trash that contains glass.

Throughout civilization, many communities have dumped their trash in oceans or other freshwaters such as lakes, rivers, and streams. While much of the trash decomposes in waterbodies over time, glass, on the other hand, changes in its composition.

Over time, the chemical conditions and movement of the water tumble and toss glass against sand and rocks similarly to how a rock tumbler turns stones into gems. These conditions change the glass physically and chemically, so most glass that was once shiny or dull changes into thicker rounded edged, frosty sea glass.

Sea Glass on Sea Glass Beach

The Journey From Glass to Sea Glass

It’s estimated that the process of transforming discarded glass into sea glass takes approximately fifteen to over sixty years.

The time it takes to turn a piece of glass into frosty sea glass varies depending on its location. Usually beaches that have more wave activity and higher pH levels transform glass into sea glass more quickly than other beaches with relatively little wave activity and lower pH levels.

pH levels for water range from 1 to 14 with 7 being neutral. pH levels below 7 are said to be acidic, and pH levels above 7 are said to be basic or alkaline. Seawater tends to have pH levels of at least 8, and fresh waterbodies like lakes, streams and ponds tend to have pH levels ranging from 6 t0 8. There are, however, exceptions. Lake Erie, for example, is a freshwater lake with a normally above average pH level between 8 and 9; the lake is famous for its frosty sea glass.


Sea Glass or Beach Glass

Generally, most sea glass enthusiasts and collectors call glass from oceans and other bodies of saltwater sea glass and glass from fresh water sources beach glass. Sometimes, however, the terms are used interchangeably.


History of Sea Glass

Sea glass can be found all over the world. It has existed since humans started making glass before 2000 B.C. in Mesopotamia. Most sea glass today, however, comes from the 19th and 20th centuries.

Throughout history, many civilizations close to shipping lanes and shores dumped their trash in nearby waterbodies because the water carried it away. While dumping it in the water made sense years ago when populations were smaller, after populations increased and thus waste increased, people realized the harmfull effects on the ecosystem. Today more people recycle, and more drinking bottles and other containers are made of plastic instead of glass.

Nonetheless, each piece of sea glass has its own history. First, it was created for a specific purpose. Its original source was part of a man-made object, such as a bottle, container, or item of household glassware. It was produced from base elements such as sand and lime. Other added chemicals and manufacturing processes varied depending on the desired color.

After the glass was discarded and made its way into water, the tumbling against rocks and broke down into smaller pieces.

Sea Glass


Sea Glass Goes on an Epic Journey

Each broken glass shard that made its way back to the shore tumbled through the water on its own journey. It constantly tossed around in the water, and its rough edges smoothed through years of erosion. Its shaped changed and developed through a lengthy process called hydration where it thickened and the soda and lime contained in the glass created a frosty pitted patina on its outer surface.

While some sea glass pieces became round or square, most changed into a triangular shape, although some locations around the world are known for more rounded or jellybean shaped sea glass shards.

Frosty Cobalt Blue Sea Glass




Common Sources of Sea Glass

Anything that was glass and found its way into the ocean can become sea glass.

Most sea glass comes from discarded beer and soda bottles in common colors such as Kelly green, brown, and white. After automation in the early 20th century, the production of glass increased. Consequently, the amount of glass dumped into the oceans increased but only up until the 1960s and 1970s when conservationists realized the importance of recycling and the effects of polluting the environment. Still, however, Kelly green, brown, and white are the most common colors of sea glass.


Uncommon Sources of Sea Glass

Most rare sea glass comes from glass produced before automation. Rare sea glass that come in a rainbow of colors such as orange, red, yellow, pink, purple, and turquoise likely come from tableware, Depression glassware, vases, glass car lights, lamps, poison bottles, perfume bottles, ink bottles, carnival glass, and artwork. Generally, older and rarer sea glass tends to be thicker than more recently manufactured sea glass.

Unlike most drinking bottles that come from white, Kelly green, and brown glass, many sea glass shards that come in rare colors were not mass produced.


Sea Glass


Share Sea Glass Love


Rare Black Sea Glass

It’s rare, but yes, sea glass even comes in black.

In the 1700s and 1800s dark green and dark amber bottles were produced for mostly liquor, medicine and poison. The dark colored glass protected the contents in the bottle from light. These rare pieces of black sea glass are hard to find and identify because they look similar to rocks when they’re lying on the sand.

You can tell if you’ve found black sea glass by placing it in front of a bright light. A dark olive green or dark amber glow will appear through the glass.

Black Sea Glass


Depression Glass Sea Glass

During the Depression in the United States, “Depression Glass” was introduced with thinner glass and patterns in soft pastel colors such as yellow, lime green, blue, gray, lavender, and pink. These sea glass shards from Depression glass are also rare.

Pink Sea Glass Shard




Sea Glass Collectors

Many collectors consider sea glass more precious than gemstones. A lot of people enjoy collecting sea glass and place it in jars around their homes. Some collect it and sell it while others turn it into art.


Sea Glass Arts and Crafts

Many artists make sea glass into jewelry. Other creative craft makers use sea glass for a number of things like wreathes, mosaics, wind chimes, ornaments, lamps, vases, and candle holders. Windows with sea glass mosaics have been becoming quite popular.

Sea Glass Mosaic


Sea Glass Earrings


Sea Glass Vase


Sea Glass Wreath Art



Sea Glass Is Disappearing

One of the main reasons sea glass is becoming so valuable besides its beauty is its diminishing supply. As society has become more concerned about protecting oceans and other bodies of water from pollution-especially in the United States-less glass and trash are dumped along the shores or into the water. In addition, the production of plastic and aluminum for containers instead of glass has reduced the amount of sea glass.

Another reason sea glass is disappearing is people are collecting it from shores all over the world. Over the past decade sea glass collecting has been becoming more and more popular. Many popular sea glass beaches have been picked over and very little if any sea glass remains.

The gradual rising sea levels because of global warming and erosion along shorelines have also affected the quantity of sea glass. Many coastal communities dump sand onto their beaches burying sea glass deep beyond the sea glass collector’s reach.

Besides its diminishing supply, many sea glass collectors report finding smaller and smaller pieces of sea glass over the past few decades.


Sea Glass on the Beach


How Much is Sea Glass Worth?

There are several factors that affect the value of sea glass. The main thing that determines value is its color. The rarer the color and the older the piece, the more value it has to collectors.

In addition, the more frosted a shard is, the more value it has to collectors. However, some unfrosted pieces found in light surf conditions or some found in fresh water are valuable too.

Some pieces of sea glass have designs from being entangled and embedded with other objects in the water; these pieces usually have more value to collectors.

Sea glass with unique patterns or markings and heavier thickness tends to be more valuable as well as bottle stoppers, insulators, buttons, marbles, bottle necks and rounded bottle bottoms. Anything distinctive about a piece of sea glass may increase its value.

Ideally, a nice high-grade piece of sea glass should have a gem-like shape with a soft and frosty patina.



Sea Glass Locations

Sea glass is found along many beaches around the world. Anywhere there is some kind of moving water and anywhere where there has been a lot of people traffic during the past century, sea glass can usually be found. Some areas have more sea glass than others.

One of the best places to find sea glass is along rocky coastlines with good wave activity. Beaches with fine sand usually yield very little if any sea glass.

Some places popular for sea glass hunting include the northern coast of California, the east coast of the United States, Bar Island in Bar Harbor, Maine, Kaui, Hawaii, Puerto Rico, Mexico and Bermuda.


Glass Beach Fort Bragg, California

Sea Glass Beach in Fort Bragg, California is considered to have the highest concentration of sea glass in the world. After the 1906 earthquake, the City started dumping trash over the bluffs into the ocean. While much of the trash decomposed, the glass, however, broke down into smaller pieces and the movement of the water and placement of the rocks turned and tossed the glass around much like a giant tumbling machine tumbles and changes stones. Soon the glass turned into sea glass and much of it made its way back to the shore.

The City stopped dumping trash into the ocean after 1967; however, much of the glass remains on the shore transformed into sea glass.

Glass Beach in Fort Bragg, California 

Sea Glass Beaches


How to Find Sea Glass

The best time to find sea glass is one to two hours before and after low tide. Simply walk in a zig-zag pattern between the high tide line and the water. When sea glass is wet, it stands out because of its shinny appearance. When it’s dry, it tends to be frosty and a little harder to spot on the sand among pebbles and rocks.

Many collectors say they find more sea glass on the beach during the first low tide after a storm.

How to Find Sea Glass on the Beach 


Green Sea Glass Shard


Difference Between Real and Fake Sea Glass

Real sea glass that was tumbled in the ocean will have pit or nick marks in its frosted covering and have rounded edges. Sometimes natural “C” patterns are apparent in the frosted nicks. Manufactured or fake sea glass is typically more smooth, has sharp edges and has less frosting. Artificially manufactured sea glass is also usually more symmetrical, and its color may appear to good to be true.

Take a look at the photos below. Fake sea glass is on the left, and real sea tumbled sea glass is on the right. After you’ve been collecting sea glass for a while, it will be a lot easier to tell the difference between real and fake sea glass. You’ll also be able to tell the difference by the way it feels in your hand; however, as sea glass becomes more valuable, the production of fake sea glass is becoming more perfected.

Some people take genuine sea glass that hasn’t been weathered enough by natural waterbodies and tumble it in a rock tumbler. They also etch it and sand blast it to make it appear to be more valuable.

If you’re considering buying sea glass, be sure to purchase it from a reputable seller who has been in business for a while. 

Real and Fake Sea Glass


Real and Fake Sea Glass


How to Identify and Date Sea Glass

Even the most experienced collector can have a difficult time identifying and dating most sea glass. It’s rare that one can hold a piece of sea glass in his or her hand and know its exact origin. Color can provide useful information about its probable origins. Thicker pieces may date back before the 1920s, especially if they have air bubble pockets inside the glass under their frosty patinas.

The Many Colors of Sea Glass

A peculiar or specific shape of a sea glass shard can hint to its possible origin and date. For example, most sea glass marbles–except for their frosty patina–look similar in shape and color in comparison to their past land life appearances. Intact bottle stoppers, handles, bottle bottoms, bottle necks, and other distinguishing shapes may reveal a source of the sea glass.

Sea Glass Marbles

Sometimes, however, a piece may hold a better clue. Perhaps there are readable raised letters or a symbol or symbols that can be traced to a source and an approximate date. The best way to identify and date these sea glass shards is to study the patterns and colors of glass. You can do searches on ebay, for example, for Depression glass or vintage glass. There are also several glass museums in different states throughout the United States where you can learn about glass manufacturers and patterns of antique and vintage glass.

You can also check out Richard LaMott’s book Pure Sea Glass: Discovering Nature’s Vanishing Gems. The book has the most information about sea glass and its history. See why this book is so popular among sea glass enthusiasts and why it gets so many 5-star reviews. Another popular sea glass book is Mary Beth Bueuke’s The Ultimate Guide Sea Glass: Finding, Collecting, Identifying, and Using the Ocean’s Most Beautiful Stones.


Average Rating:
total customer reviews...


Leave a Reply

Your email address will not be published. Required fields are marked *