There’s nothing like ceramic cups for teatime. Ceramics are durable in a way that plastic is not, elegant in a way that metal can’t compare, and far more sustainable than paper cups, whose wax covering prevents leaks but also decomposition.

Not only are ceramics more practical and more environmentally friendly, but it’s almost a faux pas to have a hot drink in anything else. The bias toward ceramics is part of a centuries-old social ritual that predates plastic and paper—even glass and metal.

Millennia ago, our ancestors collected the soft, oozing clay from river beds and found that when exposed to significant heat, it became rigid, stone-like, and maintained its assigned shape. Without pottery, large settlements and the concurrent Agricultural Revolution would have been impossible.

Ceramics differ from metals and plastics in melting points. Because its mineral composition is the same as that of stones and mountains, its melting point is extremely high. Its liquid form would be magma, which can’t be contained in any materials we humans possess. And even if we could, the result would be a very porous, sponge-looking igneous rock. Only when exposed to extreme heat and pressure for millions of years would you get a material comparable to the stuff of mountains.

So what makes ceramics ceramics? They are comprised of various combinations of minerals, like quartz, alumina, and rust in the case of terracotta. These crystals are eroded from mountainsides and form the gooey deposits in rivers. The crystals that comprise the minerals are loosely associated until exposed to heat. If the heat is intense enough, the water gaps between the crystals evaporate and the atoms that comprise the crystals begin to bounce back and forth and eventually bond with each other. As these billions of microscopic bridges form between the crystals, they form a unified, tightly-packed super crystal.

The Eastern Han Dynasty made significant improvements to their ceramics when they began to heat clay to temperatures in excess of 2300° F. They also started adding a white mineral called kaolin to a mineral mix of quartz and feldspar. What emerged from the flames was a material that was glossy, delicate and thin enough to be translucent, while also retaining remarkable durability and strength. We now know this material as porcelain.

Porcelain’s aesthetic became a mark of royalty and wealth. European and Middle-Eastern merchants sold cups and vases, and attempted to learn the process, but it was a secret that the Chinese went to great pains to guard. The magic formula was discovered in the 1700s by the Saxon alchemist Johann Friedrich Böttger. The king of Saxony had Böttger thrown in jail, and his life and freedom depended on discovering the secret of Chinese “white gold,” as porcelain had come to be called. When he stumbled upon the mineral kaolin, he found that he could heat clay to over 2400° F, immediately submerge it in water, and it would not shatter from the thermal shock. What emerged was porcelain comparable to that of the Chinese. Böttger regained his life and freedom, and the king of Saxony amassed a gargantuan fortune. It would be another 50 years before the British discovered “fine bone China.”