The earth’s outer shell, called the crust, is mostly rock. It’s at its thickest beneath the Himalayan Mountains, where it’s 45 miles deep. Most of the rock contains significant amounts of feldspar, the most plentiful mineral on earth. The word feldspar comes from the German for “a rock easily cleaved into flakes.” When feldspar has been battered by the elements for millions of years, it breaks down into a finely-grained white clay called kaolin.
A Closer Look at Porcelain and How It Came to Be
Have you seen the images of Mars’ surface sent back by NASA’s rover, Perseverance?
You probably noticed the thousands of rocks that littered the floor of the Jezero Crater. Among them are fragments of a pale clay, rich in aluminum, the bit that makes them shiny. It’s called kaolinite, and it forms when millions of years of rainwater dissolve rocks into their component minerals.
The samples from Mars match the chemical profiles of soils found around the world in places from South Africa to Southern California. Geologists says this is powerful evidence that Mars had warm, heavy rains billions of years ago.
Kaolinite is used in everything from concrete to ceramics to cosmetics
I’d never heard of it before last week, so I was surprised to find I can buy it in powder form, as a semi-dried noodle, in lumps, or as a slurry of semi-liquid waste. You know, the muck they haul out of horse barns every day. Give it time to age properly in a slurry pit, and you can sell it as fertilizer.
Kāo-lin (period-correct) is a hill Jiangxi Province, China
Back in the days of the Tang Dynasty, it was the place local ceramic makers first found an extraordinary clay. They used it to make finer ceramics than ever before by heating it in small furnaces at very high temperatures. Their glass-like pottery was fine-grained and translucent, distinguishing it from the porous, coarser, and opaque earthenware. Stoneware is earthenware but even moreso.
What’s that ringing in your ears?
It’s the sound of very good porcelain. In China, porcelain is defined as pottery that resonates when struck. The word porcelain is derived from porcellana, an Italian slang term for a young sow’s ear, or a cowrie shell. According to the New Yorker magazine, it’s the name Marco Polo gave to a small gray-green jar he brought back to Europe.
English bone china mixes feldspar and kaolinite with bones that have been ground into ash
The official position is that the bones used are from slaughterhouse animals, usually cattle. If there isn’t an English murder mystery involving a family whose ancestors’ bones were ground up and made into the bone china plates lining the walls, there should be.
Josiah Spode was an English potter
Spode worked out a formula that called for twelve parts bone ash, eight parts china stone, and seven parts china clay. Speaking of ash, there was once a cartoon of a man tapping his cigar ash into a friend’s Spode urn and commenting, “Looks like your wife’s gaining weight.”
Porcelain is used in dinnerware, figurines, and dental crowns
I thought what about toilets, but technically, most modern toilets aren’t porcelain at all. They’re made of refined clay coated with a glassy glaze and fired at extreme temperatures. Never use scouring powder on them, never use drop-in tablets, and never stand on the bowl or the tank.
Have you ever wondered why the American Standard is a toilet?
And if that doesn’t sound like J.C. Bourque, I don’t know what does.
Budget toilets have thinner, uneven glazes that stain more easily
dgfloors.com says “When you are comparing options, the smoothness and evenness of the glaze is a better quality indicator than the brand name printed on the box.”
Go look at dry toilets on display at Home Depot, Lowe’s, Ace, or equivalent
Run your hand down the trapway as far as it can go. The entire length of better toilets is covered by a smooth, slick glaze. If any part of the trapway is rough, uncoated clay, walk away, because it will clog more often.
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* Firings are as hot as 2,500 degrees Fahrenheit, which is 1,400 degrees Celsius and 1,673.15 degrees Kelvin, which is never written with a degree symbol (°).
Bonus
Ten years ago, New York City crushed 5,000 toilets to build an artificial reef for breeding oysters in Jamaica Bay. The starter population of 20,000 oysters has grown to more than 30 million, without a single mention of Flushing.
What can I take a closer look at for you?
My name is David and I wrote this article, along with more than 500 others on this site alone. Ever since I was a kid with an insatiable curiosity and a knack for learning, I’ve observed, analyzed, and made sense of hundreds of different subjects and topics. Today, in addition to writing, I help organizations solve difficult problems requiring imaginative solutions. For more on this, drop by davidallanvan.com.
