SEA GEMS ON THE SEA SHORE // what is sea glass and how to find it

Searching for sea glass holding up into sunset

One of the surprise highlights of our beach holiday was searching for frosted ocean gems – glass worn down by the sea.

Every evening once the tide had pulled back the girls and I would wander along the Cornish coastline, scanning the brown sand for the distinctive milky glow of the sea glass.

Once chunks of broken glass these pebbly treasures have their sharp edges pummelled into smoothness by the churning motion of the water. Apparently, it takes around 30 years to round them off, while the really smooth, round pebble-shaped ones have taken up to 100 years – so they’re literally a piece of history.

Eventually, the waves push them up onto the shore, leaving them nestled in the sand for foragers to find.

I used to go beach combing for sea glass all the time when I was growing up in New Zealand, but had totally forgotten about this favourite childhood past time for decades – perhaps because I haven’t lived near the ocean for coming up to 20 years now.

These days most glass has been replaced by plastic and we know better than to throw our leftovers into the sea, so I wasn’t even sure if sea glass was even still a ‘thing’. A quick Google search, however, proved it was still quietly popular; in fact, there is an international community of people who are passionate about beach combing. There are even rules on how to find sea glass, and a scale of which types and colours are most coveted.

The first thing you need to know is that there are two kinds of water-weathered glass – as the name suggests, sea glass (also known as drift glass) is created in the ocean, where is has been thrown away, washed overboard or dumped into the sea from Victorian glassmaking factories. Beach glass, by comparison, is washed up from lakes. Often, these pieces aren’t as ‘frosted’ as sea glass, as they haven’t been subjected to the erosive action of the salt and the waves.

The glass is graded by how much of it there is, and how easily it’s found – clear glass (which becomes milky white as its ground down over time) is the most common, followed by green and brown (from beer and medicine bottles). Next you have blue, aqua and turquoise (you can see why these sometimes get called ‘Mermaid Tears’), and rarer again are those colours not usually used for bottles – pink, purple, red and yellow.

The most rare – the Queen of all the colours – is orange; find yourself one of these and you’ve stumbled across genuine treasure.

Some people keep their finds as they are, piling them into glass jars and vases; others turn them into mosaics, stained glass art, driftwood mobiles and pieces of brightly coloured jewellery. There are even Facebook groups where sea glass fans meet to ask advice, show off their latest finds and buy and swap their ocean jewels.

Searching for sea glass - beachcombing, palm full of glass

The girls and I quickly realised the best time to look was after the sea lapping at the Pentewan Bayhad pulled back, revealing all the new treasures the water had left behind. As soon as tides turned we’d set out, slowly wandering along the water’s edge, scanning the dark sands for the pale glow of the glass.

To begin with we only found pocketfuls of white sea glass, but the more tuned our eyes became the more treasures we found. At first, some emerald-green sea gems revealed themselves, then a handful of amber brown pebbles. We found a few pieces of soft-aqua sea glass, then Lil Sis came back with the first chunk of bright blue, which kicked off a spree of cobalt finds.

The more we found, the more we became obsessed with our nightly beach foraging walks. There was something really relaxing about wandering shore line at sun set as the waves lapped gently beside us, and something strangely satisfying about discovering each new sea gem and returning with our pockets groaning under the weight.

On our last day at the beach – during one final forage – I found my absolute favourite piece, a rounded glass gem in soft lavender. THEN I found out something really interesting – apparently the lavender glass starts life as white, but over the years the manganese in the glass reacts with UV light, and turns it a light purple.

After lugging our stash all the way back home (FYI: sea glass gets HEAVY!) I filled a vase with all our beach finds and they’re now proudly on display in my bedroom – a lovely reminder of our family holiday

If you fancy searching for sea glass yourself, we were searching on Pentewan, on the south coast of Cornwall. According to Cornish jewellery makers and creatives, Kernowcraft, other popular spots include St Ives Harbour Beach, Holywell Bay Beach near Newquay, Marazion Beach, near Penzance, Portreath Beach, near Redruth on the north coast and Sennen Cove, near Land’s End.

Being an island, the UK is surrounded by coastline on all sides. In theory, you could find drift glass on any of these beaches, but the most famous UK spot for beach foraging is Seaham, on the Durham Heritage Coast.

Once the site of several glass bottle and glass making factories during Victorian and Edwardian times, Seaham was also home to Britain’s largest glass bottle works, the Londonderry Bottleworks. Between the 1850s and 1921, the company produced up to 20,000 hand blown bottles every day and literally dumped tonnes of glass waste into the North Sea, which is still being worn by the waves and dumped back up on Seaham’s shores today.

Their trash is LITERALLY our treasure. 


• take something sturdy to carry your sea glass treasures in; pockets do the trick, but they’ll quickly feel weighed down (not to mention full of sand)

• time your visit for just after the tide pulls out – that’s when new sea glass gets deposited on the shores. You can literally follow water as it creeps back out, ready to claim what gets left behind

• train your eye for the pale glow of white glass worn down by the sea (the most common). Keep your eyes peeled for colours that stand out from the neutral shades of the sand; blue, green, turquoise, etc.

• walk slowly and steadily, scanning the shore for sea glass as you walk (don’t be surprised if you have a stiff neck afterwards!)

• dress for the conditions. Even summer can bring chilly treasure hunting conditions. Gloves won’t work, as you need nimble fingers, but try fingerless versions or wrist warmers


glass worn down by the sea = pinterest image

Family fairy tales and traditions – what are yours? 

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