You might know “china” as the fancy plates in your Grandma’s cabinet that  you’re never allowed to use.

But what makes that stuff so valuable anyway? Today, china doesn’t seem  particularly durable or rare.

But when the Chinese invented it, its strength and flexibility changed the world. When Europeans began trading with  the Chinese in the 16th century, the westerners went absolutely crazy for it. For hundreds of years, Europeans were obsessed with replicating China’s recipe for “white gold.” But they couldn’t figure out the ingredients.

Then in 1712, a French priest gained access to the most important porcelain-making  factories in China. And in what may be the world’s first example of corporate espionage, he stole the secret formula. [♪INTRO] One of the earliest challenges  facing humans was how to contain liquids so you could  carry water and simmer stews. And no matter where you were, for thousands of years, the  answer was usually pottery.

Pottery is found nearly everywhere  that civilizations have been. It’s a pretty simple idea: dig up some clay, mold it into a useful shape,  and bake it until it’s hard. Pottery is made of the same stuff as rocks and it's kinda hard, like rocks.

But it definitely isn’t a rock. Clay is made of minerals built  from aluminum and silicon, with other trace elements thrown  in depending on where you live. The microscopic bits of mineral crystal are suspended in water to form a gloop.

If you’ve ever dabbled in pottery-making, you know that your clay can’t be too gloopy, because it needs to hold whatever  shape you’re trying to create. Then once it’s shaped, it needs to dry out. Most of the water evaporates,  leaving just the minerals behind.

Firing, or baking the clay at a high temperature, is what turns it into not-quite-rock. Before firing, all those tiny crystal bits are sitting next to each other, but  they aren’t actually bonded. The high temperature is what gives  the electrons in one crystal shard enough energy to jump to the  neighboring shard and form a bond.

In the end, billions of those bonds will stick. The result is a continuous material, with each crystal bit linked to its neighbors. When it came to transporting  liquids, pottery was a huge upgrade from the woven or animal-skin  vessels that came before.

But it still had drawbacks. It would crack at high temperatures, and its surface was porous. Stuff like food gunk or bacteria could easily get into those pores and ruin the pot.

One way to deal with the pores was to cover them with something, like a glaze. People realized that certain kinds  of ash melt at high temperatures. So as the piece baked, the melted ash formed a glass that was quite good  at flowing over the pottery.

The glass filled in any gaps  and bonded to the clay minerals. If you coated pottery in a glassy glaze, its surface was no longer porous, making it impervious to fluids. Plus, glazed ceramics could be decorated in more ways than unglazed pottery!

But even glazed ceramics were prone to crack, which usually started in the  porous body of the material. If you could somehow incorporate  the glaze into the clay itself, then when the material was fired, the pores throughout the entire piece would be filled with strong, smooth glass. That just might solve the problem with pottery.

During the Eastern Han Dynasty, around 100 CE, Chinese potters conducted a  lot of experiments with clay, adding different minerals to it and firing their pieces at various temperatures. They eventually came across a formula that, when fired at high temperatures,  turned into a white, perfectly smooth, and shockingly durable ceramic. They had invented porcelain.

The Chinese spent the next several  centuries perfecting their recipe and decoration techniques, arriving  at their most famous form by the 1300s: a vivid cobalt blue painted  on a perfectly white background. Porcelain was so beautiful—and  practical—that in most parts of China, it completely replaced traditional pottery. It was a status symbol, and a point of pride for both the crafters and the nation.

And their pride was warranted. When Marco Polo first encountered porcelain, he wrote “It is of such beauty that  nothing lovelier can be imagined”. As trade routes expanded, porcelain made its way west and enthralled the Europeans.

By 1600, they were obsessed  with Chinese porcelain. It’s estimated that between 1200 and 1800, Europe imported 70 million  pieces of it from China! For comparison, in 1500, there were only about 60 million people total living in Europe.

Europeans had been making their  own ceramics for quite some time. But porcelain was SO much better. It was lightweight, heat  resistant, translucent, and strong.

Above all, it was a status symbol. Nobles often created entire rooms just to showcase their collections of exotic porcelain. With all this porcelain coming in, Europeans became frustrated  about all their money going out.

They were tired of importing this luxury good, and wanted to capitalize on the porcelain craze. So they tried their best to replicate it, but they kept ending up with  clunky, unimpressive reproductions. They mixed normal clay with  some glass, coating it in a bright white glaze and painting  it in “Eastern”-style art.

But these knock-offs were thick,  soft, prone to slumping in the kiln, and definitely not translucent  like Chinese porcelain was. They were missing whatever secret ingredients made Chinese porcelain so light and white. Having failed at reverse engineering porcelain, Europeans turned to espionage.

The Chinese closely guarded their  porcelain factories and processes, meaning foreigners weren’t  typically allowed to see them. Enter François Xavier D’Entrecolles. When he was just 18 years old, he joined the Jesuits and became a priest.

The Jesuit order was known for their  missionary work across the globe. But Jesuits took an oath to  do more than just proselytize. They were also instructed to seek knowledge that could be useful to the King.

It was with this joint mission  that D’Entrecolles moved to China in 1698, where he thrived intellectually. He was gifted in Mandarin, which allowed him to translate books and to  strongly connect with the locals. He was also very interested in  science, and took notes about silkworms and the production of  artificial flowers and synthetic pearls.

He even wrote about smallpox  inoculations he observed. D’Entrecolles, like many others,  was also interested in porcelain. He started by referencing books on porcelain-making that were written in Mandarin.

Not learning much from the  vague descriptions in the books, he used his connections with  the local community to gain access to the factories in Jingdezhen,  the porcelain capital of China. Inside, he carefully documented the process. Catholic converts who worked  in the factories were eager to answer D’Entrecolles  questions about their craft, and offered additional insights and explanations.

Proud of having figured out what baffled so many, he compiled his notes into a very long letter, and sent it back to France,  postmarked in September 1712. But before I tell you what was in the letter, a quick ad. Thanks to Incogni for  supporting this SciShow video!

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And, ultimately, they help  you stay on the internet so you can keep finding  cool stuff like this video! In his letter, D’Entrecolles wrote, “The material of porcelain is  composed of two kinds of clay. One called Pe-tun-tse, and the other Kao-lin.

The latter is disseminated with  corpuscles, which have some shimmer, the former is simply white  and very fine to the touch.” The first ingredient, petuntse, is  sometimes just called porcelain stone. It’s made of feldspar and quartz-rich rock, which are the two most abundant  minerals in the Earth’s crust. While petuntse isn’t rare, it’s  important that the minerals in this porcelain stone are the same  minerals that can turn into glass.

D’Entrecolles went on to describe an elaborate process for preparing the petuntse, which involved finely pulverizing the stone, washing the powder several times, then forming it into bricks  which were dried for storage. Kaolin, on the other hand, seemed  to require very little preparation. It only had to be mined from  deep within a mountain side.

It’s likely that kaolin was  actually a misspelling of “Gaoling”, the city in which the clay was mined. This was just a local name for the clay, rather than a description of its minerals. It was special because it was  incredibly flexible and strong.

This allowed the porcelain to be shaped into very thin vessels without slumping over. And those “corpuscles, which  have some shimmer” that D’Entrecolles noticed in the  kaolin were probably mica, which is often found in kaolin deposits. For the best porcelains, petuntse and kaolin would be mixed in equal proportions.

But it wasn’t just the ingredients  that made porcelain special. The other secret was its high firing temperature. The knock-off porcelain in Europe  was being fired at temperatures of about 1200 C.

But true porcelain  had to be fired at around 1500 C. The kaolin doesn’t melt at that  temperature—the mineral crystals in the clay form the strongly linked  scaffold that we expect in pottery. The petuntse, however, does  melt at this high temperature.

The feldspar and quartz become a glass that fills all the pores throughout the material. Those two ingredients, and the  unique firing, were the keys. In the rest of his letter, d’Entrecolles  described the kilns, glazes, and colors that the Chinese used  to decorate their porcelain.

When the French received his letter, they finally had an instruction  manual for producing white gold. But despite their espionage,  they continued to struggle. To be fair, d’Entrecolles didn’t  know the specific mineral names, only the local names and what they ooked like during various stages of production. “Just take some powdered white rock and mix it with some powdered white clay, duh!” Even if he had given them exact chemical formulas, they still would have had to find the  proper mineral deposits in Europe.

So the French did the only  thing they could think to do: they kept stealing. As it turns out, a German alchemist had discovered kaolin around 1709. He had figured out the recipe for  “white gold” through experimentation aaaand also because his king had  imprisoned him until he did so.

So that’s pretty strong motivation. Using this recipe, the Germans had quietly opened a porcelain factory in 1710. The French sent spies and offered bribes in continued attempts to get  the process exactly right.

And they finally got their own  factory running around 1770 and published a book with detailed instructions for mining the materials and producing porcelain. Which is kind of a surprising shift to an Open Source mindset, in my opinion. But it allowed everyone to make as  much of the stuff as they wanted.

Having made a huge contribution  to European progress, d’Entrecolles continued proselytizing  in China until his death in 1741. We’ll never know exactly what his intentions were when he stole China’s biggest secret, but his espionage did change the game for Europe. Porcelain became more accessible  in the West, and European scientists continued riffing on  Chinese ceramicists’ success.

In fact, the British ended up  with a recipe for bone china, which is probably the type that  your grandma has in her hutch. Bone china is made of 25%  feldspar, 25% kaolin, and 50% … you guessed it … bone ash. Bone china is even more resistant  to chips than porcelain is, which is probably why it gained such broad  popularity in the 1900s and beyond.

But porcelain is an amazing material, and the Chinese were way ahead of their time. Despite its daintiness, porcelain’s unique chemistry makes it resilient to heat and cracks. And its glassy finish makes it easy to clean!

This stuff reshaped both  economies and daily lives. All that to say, it isn’t only sentimental value that makes your grandma’s china so special. [♪OUTRO]