What Is Sea Glass? A Guide to Finding & Identifying Cornish Sea Glass
I still remember the first time I really looked at a piece of sea glass. Properly looked. I was on a dog walk along the shoreline in Porth, Newquay, the tide had just gone out, and this tiny frosted green shard was sitting right there between two stones, catching the morning light like it had been left there on purpose.
That was the moment I understood the magic of it. Sea glass isn’t just glass. It’s something the ocean has spent years quietly transforming, sometimes decades. And once you start seeing it, you really can’t stop.
My mum is one of the best sea glass hunters I know. She has this incredible instinct for spotting colours that most people walk straight past. Some of the most beautiful pieces in my studio came home in her coat pocket first. In this guide I want to share everything I’ve learned about sea glass: what it is, how it forms, and what to look for on Cornish beaches.
What Is Sea Glass, Exactly?
Sea glass starts life as ordinary glass. Old bottles, jars, glassware that found its way into the ocean, often many decades ago. Once in the sea, the waves slowly do their work.
As each piece tumbles against sand and stone, the sharp edges soften and the surface becomes naturally frosted. The saltwater etches into the glass over time, stripping the shine and leaving something completely transformed. This process takes anywhere from 20 to 50 years, sometimes even longer.
What eventually washes up on the beach is something that cannot be faked or manufactured. Every piece has its own shape, its own weight, its own story. No two are ever identical and that’s exactly why I love working with it.
Sea Glass Colours Found on Cornish Beaches
The colour of a piece of sea glass tells you something about where it came from. What kind of bottle or vessel it once was, and roughly when it might have entered the sea. Here’s what you’re most likely to find along the Cornish coastline:
Green Sea Glass (Common)
Green is the colour you’ll find most often. It comes mainly from old beer, wine, and mineral water bottles that were produced in huge quantities throughout the 19th and 20th centuries. The shades vary so much too, anywhere from pale sage to rich deep emerald.
I love working with green pieces in the studio, especially the darker emerald tones. When the light catches them in a pendant or ring setting they have this warm, almost jewel-like quality that feels so connected to the sea.
Brown Sea Glass (Common)
Brown and amber pieces come from old beer bottles, medicine bottles, and food jars. Once the ocean has worked its magic they take on this warm honey-like tone. Really earthy and soft, nothing like the harsh brown you might expect before you’ve seen a piece up close.
My mum almost always spots the brown pieces before I do. She has a real knack for finding them tucked between rocks where I’d walk straight past.
Blue Sea Glass (Rare)
Blue sea glass is far less common. Aqua and soft blue pieces usually originate from vintage medicine bottles or decorative glassware, while deeper cobalt blues came from ink bottles and certain old poison bottles produced in the late 1800s.
Finding a cobalt blue piece is a proper moment. They’re the ones that tend to become the centrepiece of a design rather than just part of it. They really do demand to be shown off.
Purple Sea Glass (Very Rare)
Purple sea glass has a really fascinating origin. Many pieces actually started out as clear glass. Older glass was made with manganese as a clarifying agent, which slowly turns purple when exposed to decades of sunlight. So what looks purple on the beach was once completely transparent.
I haven’t managed to work with a purple piece yet, however, mum was lucky enough to find a small piece in Falmouth, Cornwall, which now lives in her rare jar.
Red Sea Glass (Extremely Rare)
True red sea glass is the holy grail for collectors. Most pieces came from old ship lanterns, decorative glassware, or vintage tableware. Items that were never made in large quantities. Finding red sea glass on a beach is genuinely considered a lucky discovery among collectors.
I’ve been lucky enough to find a few pieces myself and each time it felt like a little gift from the tide.
Where to Find Sea Glass in Cornwall
Cornwall’s coastline is one of the best places in the UK to find sea glass. The combination of Atlantic swells, rocky shores, and the area’s long maritime history means there’s a real abundance of ocean-worn glass to discover if you know when and where to look.
The best time to go is after a storm or at low tide, when the receding water leaves fresh deposits along the shoreline. Cove beaches and spots sheltered by headlands tend to trap glass and hold it rather than washing it back out, so those are really worth exploring. Rocky foreshore areas where glass can lodge between stones are often more productive than wide sandy stretches too.
Living in Newquay, I find pieces on almost every walk along the coast. The trick is just to slow down and look carefully. Sea glass hides in plain sight a lot of the time, blending in with the pebbles until the light catches that tell-tale frosted surface.
From the Beach to the Studio
When I bring sea glass back from a walk, or when my mum arrives at the door with a little collection from her latest coastal adventure, I carefully clean and sort each piece before I start thinking about design.
Because every fragment is naturally shaped by the ocean, I always work with the glass rather than against it. I never try to force a piece into a template. The shape it arrives with tells me what it wants to become. The result is jewellery that feels organic and honest, something that carries a little of the Cornish coast with it wherever it goes.
Each piece is handcrafted using recycled sterling silver or gold vermeil, keeping everything as close to the natural material as possible. No two pieces of sea glass jewellery from the studio will ever be identical. The ocean made sure of that long before I got involved.
Take a Piece of Cornwall Home With You
Every piece of sea glass I work with has already made an extraordinary journey. Worn smooth by the Atlantic, shaped by decades of waves, and finally washed ashore on a Cornish beach. All I do is give it somewhere beautiful to live.
If you love pieces that feel connected to the coast, that carry a little wildness and history in them, I’d love for you to have a look at the collection. Each one is handpicked and handcrafted, and each one is genuinely one of a kind.
Shop the Sea Glass Jewellery Collection
Want to learn more about sea glass colours and where they come from? I put together two short videos all about it, have a watch:
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