Sea Glass

Sea glass is variously described as mermaid’s tears, shards, beach glass and flotsam or jetsam. (Flotsam is from the sea and jetsam from a ship or boat). Whatever you call it, it has been around for hundreds of years, ever since people began using the ocean as a dumping ground. Over time the sharp edges of broken bottles and jars are worn away as they are repeatedly tumbled against sand and pebbles. (Sand is a mixture of quartz, limestone, coral and shells). That and the action of salt water on glass turn it into a thing of beauty.

People the world over have been attracted by the look and feel of mature sea glass, also called ‘finished’ sea glass and have been collecting it to turn it into something that may be worn, or displayed. It can also be simply left lying around. Whatever is done with it, the compulsion to collect is strong and this guide will tell you why.

What is Sea Glass Really?

Sea glass is glass washed up on the seashore. It probably began life as a bottle or jar and was discarded from a ship, boat or seaside pub. Sometimes it was lost overboard or was part of a ship lost at sea. In some parts of the world whole cars were dumped on the beach. It can also be found in lakes, rivers and estuaries and could be from an old bottle dump, or any kind of ‘waste recycling scheme’ located on the shore. It is also free.

Glass is one of the oldest man-made materials. The Romans made glass. (Natural glass may also be turned into sea glass. Volcanic action, meteorites and lightning may turn natural materials into glass. Obsidians, fulgarites and tektites could end up in the ocean, to be turned into sea glass.)

There are many different kinds of commercial glass but the ingredients are predominantly silicon dioxide (silica), made from sand, and various other elements to make it easier to manufacture. The most common form of glass is soda-lime glass. Glass is coloured by adding other substances such as iron oxide and carbon. Most glass found on beaches is white, or green, known as sea foam. The less common colours are blue and red and collectors prize these. In addition to glass from bottles and jars, marbles and beads are also collected. The rarest sea glass could possibly originate from the red and green lamps carried by ships at sea to denote the port and starboard side of the ship. Very old wine bottles were made from a dark green glass (almost black), which is also prized.

Glass has a close connection with chips, the kind used in computers and other digital devices. These are also made from sand. In fact sand is probably the most important substance on the earth, even more important than oil. But that’s a secret until the Researcher has acquired the mineral rights to several deserts and beaches.

The most important attribute of finished sea glass is that it should not have any sharp edges. Mature sea glass has been subjected to many years, decades and even centuries of what is called ‘wave action’. As you probably know, waves are caused by the wind and tides. This gives it a sumptuous look and feel, much like parts of the human female.


Seawater contains around 3.5% salt, and as everyone who ever cleaned his or her teeth with it knows, it can take the enamel off in seconds. Salt has a chemical formula and it is dangerous if you eat too much of it. Seawater and carbon dioxide form a mild acid called carbonic acid. Its action on glass is to turn the silicon dioxide into something else. (That’s a PhD thesis in itself). Old sea glass looks as if it is covered in frost. Any sea glass that isn’t frosted when it is dry isn’t worth having and should be returned to Davy Jones. When it’s wet, you can’t see the frosting, as the glass emits an inner glow, which is probably even more attractive on a sunny day than frost on a cloudy one. Some people oil their sea glass to make it appear wet, permanently hiding the frosting. This is a question of taste.

Where is Sea Glass Found?

A good place to start is beaches close to working or retired ports because that is where a lot of rubbish was thrown into the sea. Old dumps are also important sources of finished sea glass. Glass Beach in Fort Bragg, California is a spectacular site as it contains a huge amount of sea glass from old dumps. Some dumps were set alight to reduce the amount of rubbish on the beach and this melted some of the glass leading to a special type of sea glass known as bonfire glass.

How is it Collected?

A lot depends on the type of beach. Mostly it may be retrieved by simply picking it from the surface of the beach, but if there are rocks, large waves or the beach is inaccessible from the land, other measures are needed. It is not unusual for Wellington boots to be worn, and some collectors also don wet suits, snorkelling gear or fully equipped scuba diving outfits. Some people use kayaks and ropes to get to tricky beaches.

A wooden spoon may be employed to explore nooks and crannies. On no account must anything made of metal be used as this could damage the glass.

An important consideration is the state of the tide. If you go to any beach the chances are the tide is either coming in or going out and it does this twice in a twenty-four hour period. The height of the tide also changes over a twenty-eight day period during which time it will change from a spring tide (the highest tides) to a neap tide (the lowest tides) every seven days. Spring tides happen because the moon and sun are pulling the water in the same direction; when there is a new moon or a full moon. At other times in the cycle the sun and moon are not in synchronism and the tides are smaller. This means that the beach is never the same. Currents and wind also contribute to tides and what is left behind on the beach.

Tide timetables are an essential tool of the sea glass hunter. A low tide or after a storm are the best times to collect. Look for pebbles because that is where the sea glass hides. Mainly.

What Happens to Collected Sea Glass?

Almost anything can be done with sea glass from placing it inside another glass container to recreating the crown jewels. Light catchers are a favourite, as are models of fish, mermaids and other sea creatures. Many people earn a living by making sea glass jewellery such as pendants, necklaces, cufflinks, bracelets, earrings, brooches and rings. The sea glass used is normally referred to as ‘jewellery grade’.

Sea Glass and Photography

Sea glass is usually found in scenic parts of the world where the conjunction of sky, sea, sand, rocks and some man-made buildings combine to make interesting scenes, ideal for photographing. Some of our most iconic buildings may be seen such as piers, lighthouses, jetties, and ships and boats of all kinds and sizes. It is not unusual for sea glass collectors also to be avid snappers and some are excellent photographers. Not only do they photograph their beaches but also their finds, before and after sorting, and sometimes during. Now, because of the Internet there are social community websites where seaglassers gather from around the world to compare photographs and collections. Weird.