What is sea glass?

What is sea glass and how is it used in jewellery?

Having not really been aware of sea glass for most of my life, I’ve recently been forced to sit up and take a bit more notice…

  • Pinterest pictures of sea glass projects have popped up whenever I was pinning.
  • Facebook pages have been full of discussion about where to find the most beautiful samples.
  • New sea glass jewellery suppliers have been showing off their beautiful creations.

Sea glass is obviously the new black

All this has inspired me to read up more about what is sea glass and how to make sea glass jewellery. I’ve also been sea glass hunting – a surprisingly enjoyable, relaxing and addictive pastime. There also seem to be many ways to combine sea glass with silver and copper as part of my portfolio for the silversmithing even class I’ve been taking at Leeds College of Art.

During my recent week away in Northumberland I realised that the beaches there are quite well known for their stocks of beautiful sea glass. It would have been a waste not to take a look round for some while I was there and I was surprised and delighted to find many different pieces.

Some of the best were from Seaham beach near Sunderland and I collected the best ones I’d found into one little group to take a picture. I love this photo – I put them in a glass dish so the light would shine on them but it was very bright so I decided to take the picture with my back shielding out more of the sun. As I lifted the camera, a shaft of sunlight got in on the act under my raised arm. Stunning result (always meant it to happen, of course).

What is sea glass? Sea glass in a sunbeam


What is sea glass?

Basically, sea glass is a marine pollutant. A pretty pollutant but still waste, nonetheless. It is not a natural substance – it is manufactured glass that has been either thrown into the sea deliberately or has ended up there by accident.

Sea glass has then been polished and made into fragments and smooth pebbles by the churning action of the waves. People throwing beer bottles and other glass into the sea from a seaside pub might be responsible for some sea glass but there are other, more interesting ways it can get in there.

What is sea glass? Pale green sea glass
Pale green sea glass

Sources of the best sea glass

The best sea glass comes from antique glass that has been in the sea for a long time, sometimes over 100 years.

Seaham beach sea glass

The Candlish family had their massive bottleworks in Seaham, near Sunderland on the north east coast of England, between the 1850s and 1921.During those years the glassworks thrived and became one of the biggest glass manufacturers in the country. It closed during the coal strike of 1921 in the depression as the first factories to mass-produce glass opened. You can read more about Seaham Harbour and the glassworks in this article.

At the height of its success, the Seaham glassworks was producing 20,000 hand blown glass bottles each day. At the end of the day, the final large balls of glass used for blowing bottles became unusable so were thrown into the sea. This end-of-day glass often contained different colours of glass and so, if you’re lucky, do the polished end-of-day glass fragments that you can find on Seaham beach.

What is sea glass? Two colour seaham beach sea glass
Blue coloured end of day sea glass from Seaham beach
What is sea glass? My best piece of Seaham beach sea glass
My best piece of Seaham sea glass

Glass lost at sea

Large consignments of Seaham glass bottles were shipped out of Sunderland for export but during the First World War, in March 1917, the Oakwell, one of the main carrier ships, was sunk by a mine. Its entire contents of glass was lost, just off Robin Hoods Bay.

No doubt other batches of cargo also ended up in the water due to storms and weather, so you have a good chance of finding antique sea glass along the entire east coast from Holy Island down to Scarborough.

What is sea glass? Beautiful Seaham beach sea glass
Beautiful Seaham beach sea glass

Not all sea glass is equal

The pieces I found at Seaham are lovely. Gorgeous colours and polished to pebble shapes.

The rest of my sea glass came from other places – Boulmer beach and Craster harbour were good sources. The glass from these beaches is a mixture of the good, the bad and the just plain ugly. I collected some of all types as I have read that drilling any glass can be tricky. The glass I can’t use for jewellery can be used in other crafts and the really ugly pieces will be for practice.

Craster harbour - a little beach with a lot of sea glass
Craster harbour – a little beach with a lot of sea glass
What is sea glass? Craster sea glass
Craster sea glass
What is sea glass? Aqua sea glass from Boulmer beach
Aqua sea glass from Boulmer beach
Ugly sea glass for practice drilling
Ugly sea glass for practice drilling

17 thoughts on “What is sea glass?

  1. Anne says:

    we’re heading to Scotland and England in a few weeks. Any other hints on the western Scottish borders and northwest England? Great site!!

    • Crafternoon Treats says:

      Hi Emma – wow that’s a major haul – will have to fit in a visit to Easington sometime 🙂

  2. Linda Jereb - By The Sea Jewelry says:

    Great article! You are right about the Candlish glass but that only accounts for the more common colors (green, brown, white, seafoam and possible some aquas).
    The multi color glass could not be from bottles but only from art glass which originated more from Sunderland and the defunct art glass factories on the Tyne.

    • Crafternoon Treats says:

      Hi Linda – yes, I believe the was a large glass factory at Seaham, which is why its such a good beach for sea glass hunting xxx

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  4. Lucy@Attic24 says:

    oh you’ve been to Craster!!! Lucky you, and I too have a great haul from there and Boulmer. Holy Island too, with lots of beautiful sea washed pottery on that beach.
    Can’t wait to see what you do with it, I have always wanted to make sea glass jewellery, I have glass still that I collected as a child, it’s been a lifelong obsession!

    • Crafternoon Treats says:

      Hi Luce, yes I found loads of aqua coloured sea glass at Craster and Boulmer but hardly any sea pottery. My best pieces were from Seaham near Sunderland – bit further down the coast. Another fab beach and antique sea glass pieces in their thousands because of the glass factory that was open for decades til 1921. I’m trying to set some pieces with bezels and claws rather than drilling them – that would be far too stressful cos they get heat shock and break! x

  5. Jane G says:

    Having spent some of my childhood in the North East, we’d always come back with some sea glass. I didn’t ever dream it would become as popular as it is now. Think I’ve still got some tucked away

  6. Susan says:

    Oh, I do love beach glass. Having lived most of my life on Long Island, I was very familiar with sea glass. You have some beautiful pieces though. I’ve never seen the end-of-the-day glass with the multi colors. It’s quite unique and just beautiful. I can’t wait to see what you make with it.

    • Crafternoon Treats says:

      Thanks for your lovely comment – yes I am keen to make some jewellery that sets it off nicely. No drilling for those best pieces though! x

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