Sea Glass Colour & Rarity Guide

WHAT IS SEA GLASS?

Discarded glass that has been transformed over decades, sometimes centuries by the ocean waves, the magic of sea glass has captivated me for years! From shiny shards long forgotten to smoothed frosted jewels lying on the sand waiting to be discovered... here is your guide to the origins of the many different hues of sea glass and their rarity.
All sea glass pictured is from my collection, found along the Northern Irish Coast over the past 10 years. We'll start with the most common colours and finish with the truly rare 'happy dance on the beach' finds. Hopefully you find this guide useful for your own beach adventures, I'd love to hear from you if it is! 

COMMON SEA GLASS COLOURS

WHITE SEA GLASS
Found in various shades of cool and warm white, it was originallly clear glass that has become cloudy during its time being tumbled in the waves. The most mass produced bottles were made from this white glass, such as medicine bottles, lemonade bottles, milk bottles etc. also some food containers and Mason jars, plus window glass. 

BROWN SEA GLASS
From amber to the deeper brown hues, this is another very common beach find. Mainly from beer, whiskey, early 1900s liquor bottles, medicine or bleach bottles, you'll probably come across brown sea glass quite easily when beachcombing.

KELLY GREEN SEA GLASS
This bright vibrant green (named after the Irish surname Kelly) is a common but beautiful beach find. Mostly the result of beer or soft drink bottles from the 1800s right through to the mass production of the 1950s onwards, which is why there is so much of it strewn across our beaches. The chromium oxide used in the manufacture of the glass creates this strong, bright green associated with vitality, nature and renewal. As the green tint was used to protect the contents from light, it was also used in pharmacies to store ingredients and extend their shelf life.

LESS COMMON COLOURS

SEAFOAM SEA GLASS 
Less common, seafoam blues and greens represent ocean colours perfectly! Mainly from late 1800s / early 1900s soda bottles, mineral water, baking soda, ink bottles and mason jars. The pale green seafoam shades (seen below alongside some deeper teal greens) are known as 'Coca Cola green' when all Coke factories after 1916 used this colour for their bottles. The shades of seafoam vary depending on the amount of silica used in the glass. 

 

FOREST AND OLIVE GREEN SEA GLASS
Some of my personal favourites to find, most of these green shades are from wine and beer bottles. Some darker olive greens are from very old whiskey or rum bottles, from before colourants were added. 

COBALT BLUE SEA GLASS
A truly stunning vibrant blue compared to its softer cornflower blue counterpart, this blue most likely came from late 1800s - early 1900s poison and medicine bottles, cosmetics jars, insulators, inkwells, decorative art glassware and perfume bottles. This colour makes some very striking jewellery and I personally always fall in love with every piece I find!

LAVENDER SEA GLASS (SUN PURPLES)
This is an exciting and special glass for me as it can take you by surprise...you may find the soft lilac pieces on the beach like this or you may think you have found an off-white piece that after a long time in the sun will gradually turn a shade of purple! The reason for this is that manganese was added to the glass to turn its natural greenish tint to clear / white glass by removing the iron naturally found in the sand. But over time, the manganese reacts to the sunlight and your glass can change to one of the beautful hues pictured above.

RARE SEA GLASS COLOURS

TEAL GREEN AND TEAL BLUE SEA GLASS
These rich, deep blues and greens come mainly from mid 1800s - early 1900s soda or mineral bottles. In smaller amounts it could de derived from inkwells, fishing floats, decoartive art glassware, Mason jars and insulators from 20th century telephone and telegraph poles.. Always a happy dance on the beach when one of these beauties is found!
Named after the Eurasian Teal duck, it is a truly eye catching and sought after sea glass colour. With it being tricky to create consistent colour batches due to the balance of chromium, cobalt and iron during the manufacturing process, limited batches were produced, hence its rarity.

GREY SEA GLASS
Every time I find a thick frosted piece of this gorgeous glass, I immediately think of the old TV screen that it probably came from. Also could be from depression era glassware. The deeper or 'true' greys will contain iron oxide or selenium. Some lighter shades of grey sea glass from tableware could be white glass containing lead that has gradually turned grey over time in the sun.

PURPLE SEA GLASS
As you can see from the picture above, true deep purple sea glass is very rare indeed! I've only found a few pieces in 10 years and each one has had me shouting for Coppertop to come and see it! In fact, the incredibly rare purple sea glass faceted bead at the front of the picture was found on one of my first ever sea glass hunting trips. I had no idea at that point just how lucky a find that was and still remains one of my greatest treasures. 
Derived from decorative art glassware, tableware, perfume bottles, vases, fishing floats and ink bottles, true purple glass contains manganese and iron.

YELLOW SEA GLASS
Aren't they just beautiful?! Like little pieces of captured sunlight, yellow glass is highly sought after. Likely from Depression era glassware, art glass and vases. Some light yellow glass can actually be clear sea glass that has turned yellow over time in the sun due to the selenium content in it.

PEACH / PINK SEA GLASS
Another rarity for me especially is this gorgeous soft peach or pink glass. I have only found two true pinks in 10 years and parted with one of those last year for a special custom order (see my custom order page for a picture of it). Mostly derived from tableware , perfume bottles, vases and decorative glassware, some clear glass will appear light pink over time if left in the sun due to the manganese content.

RED SEA GLASS
Aaahh red sea glass, one of the colours that holds the most excitement for me! True reds contain actual gold to turn the glass red though Anchor Hocking found a way to use the less expensive copper in the glass to make it red, meaning they were able to produce more of it. Mainly from Depression era glassware, art glass, tableware, Victorian oil lamps, car tail lights and my favourite ones - from ships' signal lanterns! I always love the thought that any red I find could be from an old shipwreck.
There is also the Amberina glass which you can see at the top of this picture which is a two - tone yellow glass merging with red, originally produced in the late 1800s to early 1900s.

ORANGE SEA GLASS
As you can see from this picture...orange sea glass is pretty much the Holy Grail for sea glass hunters. This is the grand total of orange glass that I've ever found - two pieces and one of those is absolutely tiny! Mainly from decorative glassware or tableware, it was also used in auto / marine reflectors and signal lamp lenses on ships' warning lights.

BLACK / PIRATE SEA GLASS
So this doesn't look very exciting but to me, I'm always thrilled to find pirate glass!! So named due to the old bottles that would have been aboard the ships in the 1700s and 1800s made from this glass. There is no true 'black' glass, this is actually very dark olive green or amber glass but due to the thickness of it, very little light shines through. You can just see a little of the green and brown light in the photo above! It can be very hard to spot black sea glass on the beach as it looks so much like stones. Sometimes you might even find 'black' glass that is actually thick red, blue or purple from old insulators. 

UV / VASELINE GLASS
Nothing beats the dramatic effect of shining a blacklight torch over a jar of glass and seeing that distinctive bright glow! Or finding a piece on the beach and getting excited thinking it might be UV glass and having to wait until you get home to check. UV or Vaseline glass is a type of decorative glassware made in the late 1800s and early 1900s.
 It contains a very small amount of uranium which gives this green glass its impressive fluorescence. It got the nickname 'Vaseline glass' due to the yellowish-green colour resembling the petroleum jelly. The production of Vaseline glass dropped hugely in the 1940s due to uranium supplies being used for World War 2.
There are also certain reds and oranges that will glow under a blacklight, containing selenium and cadmium. Some sea pottery could have UV in its glaze ingredients. You may even be lucky enough to find a sea glass marble that has a UV swirl in it! Speaking of marbles...

ULTRA RARE SEA GLASS

SEA GLASS MARBLES
Sometimes I can't believe how lucky I am to have found so many sea glass marbles over the years, including two partial German handmade marbles! These were larger marbles with lots of swirled colours (you can see one at the front of the picture above). These would have been played with by Victorian children on the beaches and lost in the sand or down drains, for us to find many years later! The smaller colourful marbles could have been used as ballast on ships that were dumped out before they returned home with their cargo, but more likely to have been also playing marbles for children or cargo spill from Japanese boats exporting the cats eye marbles they invented in the 1940s. 
Sometimes you might find a slightly larger plain white marble from the late 1800s known as a Codd marble which would have been used to seal carbonated drink bottles, much like the current Japanese Ramune drinks. Which leads nicely into our final category...

SEA GLASS BOTTLE STOPPERS
These bottle stoppers are one of my absolute favourite finds, though I haven't found any now in quite a few years. Primarily used in decanters, apothecary, perfume, and sauce bottles from the mid 1800s onwards, it always feels exciting to find one intact despite many years being tumbled in the saltwater of the ocean waves!

 

I hope you've enjoyed this brief guide to the sea glass I have been lucky enough to collect over the past 10 years, that I now get to turn into new treasures for you to carry your own special piece of the Northern Irish coast with you always...