No Glass. No Pineapples.

In the northern latitudes it was cold, and pineapples don’t like the cold. There was no price high enough to make a pineapple grow outdoors in Buckinghamshire. (And you weren’t going to ship one – it would rot in the months it took to reach you.) But the demand for pineapples drove the development of ‘hot-houses’, or pineries, to grow them in. The pineapples were planted in stepped beds full of lovely fresh warm horse manure (frequently turned over), while wide panes of glass spanning the walls and angled roofs performed a precious function: trapping the sun’s heat inside, keeping this little dung-den cosy enough for the fruit to grow.

Glass is like that. An often overlooked – or literally looked right through – crucial element making the impossible possible. In the Georgian era, sure, it just helped rich people get a taste of pineapples. But in the Medieval period, glass had a somewhat holier mission: it helped poor people get a taste of God.

Stained glass windows were the primary form of pictorial art at that time, and churches were one of the few institutions wealthy enough to commission them. Hundreds of pieces of coloured glass were arranged to depict biblical scenes – illuminated by the light shining through them, they brought mesmerising, kaleidoscopic stories from the Bible to people who couldn't read. Islamic mosques also featured breathtaking stained glass, although their designs used geometric patterns rather than figurative images, which are forbidden by their scriptures.

It is entirely plausible that without glass, two of our major world religions wouldn’t have caught on the way they did.

Jump to the current day, and glass is ubiquitous, it's on every building you look at. But even better than bringing us God, it's bringing us God-like technologies that once seemed like magical thinking. Did you just FaceTime your new baby niece on the other side of the world? That was Brought To You By Glass. Had laser eye surgery and can now see? Thanks, Glass. We're adorned in and surrounded by the stuff. It is the key to the connectivity of the modern world – we cannot live a digital life without it. It's our watchfaces and smartphones and TV and computer screens. It's the fibre optic cables that carry information across the internet and deliver it to our watch faces and smartphones and TV and computer screens. You might even be charging all these gadgets with energy from the sun which is converted by the solar panels on your roof. (Glass, you've done it again!) Some even argue that we should label our current era The Glass Age – a time defined by this material.

Anyway – pineapples. The 150 years of "pineapple mania" is now recognised as such a significant phenomenon that it has its own chapter in art history books. (If you want to know just how nuts it all got, look up the "Dunmore Pineapple" in Scotland. This pineapple castle looks like an AI-creation designed to bait boomers on Facebook but is entirely real.) Nowadays, if you want to impress visitors with a pineapple on your dining table, you'd need to drop a grand on a Swarovski crystal¹ pineapple. Which is, of course, glass. See? It all comes back to glass. And our connection to glass goes all the way back to the Stone Age...

Glinting in the ground

The first caveman to notice a dark glimmer at the edge of an old volcano would have had no idea he (or she – no reason this couldn't have been a cavelady!) had stumbled upon one of the most important materials for humanity: Obsidian is the naturally occurring form of glass. It is created when lava cools quickly, leaving behind a black², brittle, shiny rock. Our Neolithic ancestors worked out that breaking these lumps up in certain ways produced very sharp edges, which they fashioned into arrowheads and blades and scrapers and other tools. Probably not ornamental pineapples, though. One presumes they had higher priorities than that.

Several hundred thousand years later, humans finally went into competition with volcanoes, and started making glass themselves. Glass beads from around 3500 BCE are one of the oldest known human-made glass objects, though they are thought to be an accident: a by-product of metal making found in Bronze Age slag. Whether people in Egypt or the 'Near East' of modern-day Iraq were the first to make glass on purpose is unclear. The important thing is someone worked out that melting sand mixed with a sprinkling of other ingredients, then cooling it down really quickly, got you glass. Hooray!

By 650 BCE, the Assyrian king Ashurbanipal had a 'glassmaking manual' in his library – recorded in a set of cuneiform³ instructions chiselled onto stone tablets⁴. So, sure, they were literally 'set in stone'. But the truth is any glassmaking 'instructions' should be seen as more of a guide, really, because the whole thing is pretty much alchemy. There are all kinds of chemical mixes you can use to produce glass, and all kinds of different results you can get. The usual equation is sand (silica) + soda (sodium carbonate) + lime (calcium oxide) x really high temperature⁵ & fast cooling = glass. But you can use quartz pebbles and potash instead. You can adjust the temperature of your furnace depending on the recipe you're using, your glass can be transparent or opaque or coloured. Add a bit of cobalt for blue glass. Or lead antimonate for yellow glass. Or a different type of lead to get exceptionally clear glass (or 'crystal', see Footnote #1).

A crazy idea

For a very long time, making shapes out of glass took a very long time. You had to pour it (while molten) into a mould, or wrap it around another shape, or roll it across a textured surface to create decorative markings. It produced beautiful objects which were both useful and prestigious – but it was a fairly imprecise and laborious process. So full credit to the Syrian craftsmen who, around the time BCE ticked over to CE, decided to try something new – something a bit crazy: They decided to blow on the molten glass, through a long tube. This created a bubble, which could be much more quickly – and precisely – shaped⁶ into the desired form. The Romans quickly copied the method and spread it across their Empire, which by all accounts, was rather vast. Glassmaking went from a specialised craft to a widespread trade in an instant.

Different cultures favoured different styles of glass over time, but by the 13th century, no one was making glass quite like the Italians were. The industry was huge in Venice, where local glassmakers were renowned the world over for their skill and quality products, including spectacles lenses.

Unfortunately, the glassmakers were renowned in Venice itself for causing heaps of fires. In 1291, the city’s glassmakers and their troublesome furnaces were moved to the nearby island of Murano, partly to distance the fire risk – but also to better protect their trade secrets by isolating them from nosy visitors.

Murano glass was the epitome of luxury throughout the 15th and 16th centuries, exported all over the world, though the secrets of their glassmaking did eventually escape the island and its dominance slowly waned. And now, in the 21st century, used glass from all over the world is coming home to Murano...

Glass waste to paste

One of the best things about glass is it is almost endlessly recyclable. Glass bottles and jars can be repurposed (every nanna knows this). There's a reason you can earn 10 cents in most places for returning a glass bottle: it's rubbish with significant value. Used glass from all kinds of sources – including building and consumer waste – can be thoroughly cleaned and sorted and crushed and melted back down and turned either into new glass, over and over again, or used as an aggregate in things like asphalt and concrete.

On rare occasions, waste glass is deemed non-recyclable for one reason or another. Even that glass can overcome its fate at Rehub – a Murano-based "upcycling" plant that has developed a way of turning it into a versatile paste, at room temperature (a rather more energy-and-emissions-friendly temperature than a furnace). That paste is then pumped through a 3D printer and used to make jewellery, tableware, furniture, lights, tiles, surfaces and decorative objects. It's a brand-new, innovative, patent-pending process. And of course, basing the business on the island of Murano keeps their secrets safe from nosy visitors.

Modern glass

But no one wants to sequester traditional glassmakers away on an island, these days. Their craft is niche-to-dying as far as art forms go – or was, until Blown Away re-popularised it (for more on the important patronage of reality television, see Footnote #5). There are special ways glassmaking is being practised, revived and appreciated today – even those Syrians who first filled molten glass with their own breath would find some of it pretty wild.

The Spanish artist, Jaime Hayon, designs astonishing glass figures inspired by decorative African masks. A studio in Murano brings the components for these to life, blowing their main form into moulds and then delicately balancing the colourful adornments of stems and funnels into its openings. Iittala's Finnish glass factory creates musical wind instruments out of glass for the experimental sound artist Damsel Elysium, who said they "could see the sounds when I saw the glass being formed". Architectural glass⁷ blocks are making a comeback – but not in the frosted hollow cubes of office buildings or 1980s feature walls. This time, they're cast to create a solid prism the size of a standard brick, then polished until they're ice smooth and crystal clear. The creative and practical implications of fully transparent brick walls (sometimes integrated with regular masonry) are only just beginning to be explored.

In Newcastle, Australia, Lee and Zac Howes – a mother and son duo – use 3D printing to create moulds for glass shapes that would otherwise be impossible to achieve: a glass cube puzzle of interlocking pieces, a clutch of twisted glass cylinders that perfectly fit together. And Lee once created a glass matchbox – complete with a little drawer and matches – through a combination of casting, fusing and screenprinting.

All this cutting edge technology is exciting – but the older glass forms persist, too, and the Howes are helping to keep the tradition of stained glass windows alive. Churches commission the pair to create new stained glass windows, or to repair the ones they already have. Private individuals, too, might ask them to create a bespoke leadlight window, a couple of metres high and wide, to allow sunlight to flood their entryway through the prism of a native flora bush scene. It will take Zac around a month of full-time attention to bring this to life. (He has taken over the leadlighting8 work, because Lee’s blood lead levels are getting too high after 30-odd years of exposure.)

Ask Lee why people are so drawn to glass, and its affinity with light is a big part of her answer:

“It has qualities that nothing else has. The transparency of glass, the luminosity of glass, the glow of glass. No other substance has the same qualities. We just can't get it out of anything else. People have tried to recreate it out of resin and stuff, but it doesn’t work – it’ll stay for a couple of years, but then it just loses its vibrance.”

There are some frosted, coloured glass eggs sitting on the display shelf at the front of her shop. They do indeed glow, as if there is a small light bulb or flame set inside them. People pick them up, look underneath them, try to figure out what the secret is. Zac explains that it’s simply the glass catching the light, drawing it in. The glass egg does what the stained glass windows do, then. It transforms light into spectacle.

You won’t be surprised to learn that pineapples are a popular motif in leadlight designs. But if I wanted to impress someone with a glass object, I would choose not a pineapple, but one of Lee’s handmade glass gum blossoms. She creates each individual stamen by hand, holding a small square of glass over a flame and gently stretching it out to form a long string, which she then rests in a curved mould before firing. Then, each filament is tipped with a small yellow ‘glob’ of glass, to create the anther of pollen at the end. Hundreds of these are then inserted into tiny holes drilled into the flower’s cast glass receptacle, completing the marvel: a delicate gum blossom, made entirely of glass.

The extraordinary detail and fragility of the object forces you to ponder the properties of the material it is made from: its versatility, its mystery, its beauty and many functions – and to note how rarely we stop to appreciate that life as we know it simply would not be possible without glass.

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¹ The term 'crystal' – in reference to decorative glassware – is confusing, because glass is not, in fact, a crystalline substance. Ask a physicist, and they will explain that glass is actually an amorphous solid. You will look blankly back at them, and they'll say, "true crystals have a highly organised microscopic structure, glass doesn't". And you'll say "why do we call it crystal, then?". And then a passing historian will explain that it's because in the 1400s, the Venetian glassmaker Angelo Barovier developed a way of making totally clear glass which resembled naturally-occurring quartz rock crystal, so they called it cristallo. "Ahhh," you'll say, "So we call it crystal because it looks like crystal, but it's technically not crystal?" And then the physicist will say "Yep – and what's even crazier is that glass is technically not a liquid or a solid either. It's kind of its own state of matter." And your brain will hurt and you'll decide that's enough glass trivia for one day.

² Obsidian is usually black. But sometimes it's brown, or green. And very occasionally blue, or red, or yellow, or orange, depending on what impurities it may have mixed with. There are rules, with glass – but many exceptions to the rules.

³ Cuneiform being the wedge-shaped writing system of the time.

⁴ These instructions read (approximately): 'Take 60 parts sand, 180 parts ashes of sea plants, 5 parts chalk –– and you will get glass.' This is a fairly small proportion of sand, though, suggesting it wasn't possible to reach high melting temperatures at the time, and that the glass produced was likely soft and suitable for only basic vessels.

⁵ Hi – yes – another exception to the rule: some plants produce glass from the silicon they absorb through their roots, but without using heat to catalyse the chemical reaction that turns it into glass. No one knows how this happens. The fine hairs of stinging nettles and the skeletons of ocean sponges are examples of this mystery nature glass.

⁶ Don't for one second assume this method was any less stressful. There's a reality TV show called "Blown Away", currently in its fourth season, that is built entirely on the high-stakes drama of glassblowing. Granted, it's a format of contrived competitive glassblowing with an additional component of competitive art-wankery – but even without cameras and producers upping the ante, blowing glass involves physical strength, intense concentration, very hot fire (lots of fire) and the ever-present threat of gravity smashing your painstakingly made creation to smithereens.

⁷ The first gift glass brought the world of architecture was windows: before sheet glass was invented, any hole you put into a wall for light and ventilation was going to also let bad weather and bugs and bad guys in. So, those holes tended to be pretty small, and indoor spaces used to be pretty dank and dark. Today, glass's gifts are both practical and aesthetic – and in the hands of an imaginative architect, it will never fail to deliver breathtaking results. The extraordinary Crystal Palace, created for London's Great Exhibition in 1851, was one of the first sizable structures to be made almost entirely of glass. Since then the world has been treated to glass icons including: Berlin's Great Tropical House (1907), Bruno Taut's Glass Pavillion (1914), Philip Johnson's Glass House (1949), Ludwig Mies van der Rohe's Farnsworth House (1951), the Louvre's glass pyramid (1989), London's 'The Gherkin' (2003), and Beijing's 'Bird's Egg' National Grand Theatre (2007). (And yes, it does seem that glass buildings are getting whackier as time goes on.)

⁸ Leadlight is an umbrella term that includes stained glass windows. The distinction is generally that leadlight designs tend to use clear glass in geometric patterns, while stained glass is for colourful and detailed pictorial designs. Both styles use lead strips with channels along the edges, to hold the pieces together within the frame. Anyone working with the material needs to have annual tests to monitor exposure.

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