Ever wonder why your grandmother prizes her bone china collection and won't let anyone under 50 use it? Bone china is expensive, because it takes a huge amount of time and many steps to produce, some of them only by hand! Nevertheless, bone china is actually sturdier than anyone realizes. Take our quiz to find out why grandma should at least let you wash the dishes.
Bone china is the strongest and most translucent type of porcelain.
At the end of the 18th century, Josiah Spode developed a new method for making stronger porcelain, which involved the addition of calcined bone ash into the clay mixture.
There are four main processes: clay making, mold making, glazing and decorating.
There are five main ingredients that go into the final mix: china clay, regular clay, bone clay, flint and feldspar.
Eighty percent of china produced in the Lenox factory is white, 20 percent is ivory.
They add green vegetable dye to the ivory mix. The dye burns off when the porcelain is in the kiln.
The filter press removes air and water from the mix, leaving it with a moisture content of 20 percent.
An extruder presses the sheets of clay into tubes, called pugs, and takes out more air.
Each pugs weighs about 30 pounds (13.6 kg) and looks like a giant piece of chalk.
The pug pyramids are covered in plastic wrap on all sides to form a protective tent that maintains the correct humidity level.
The metal master molds are sprayed with a soapy mixture, the residue of which helps release the molds later on in the process.
It takes two people: one to pour the plaster into the mold and the other to spin the mold so that the plaster distributes evenly.
Though it would seem to make sense to use metal molds and save the step of making plaster molds from them, plaster molds draw out more moisture from the clay, which metal molds can't do.
Dinner plate molds can be used 100 times, while molds for more intricate items, such as cups, serving dishes and cream holders, can be used 10-15 times.
Greenware refers to clay pieces that have not yet been fired in the kiln.
Handles are affixed to china cups by hand. Part of the finishing process, before they are put in the kiln, involves checking that the handles are securely attached.
The bisque kiln, powered by gas, reaches 2,290 degrees Fahrenheit (1,254 degrees Celsius). Pieces are fired for nine hours.
It is a bath of smooth stones and water, which smoothes and polishes the china after it comes out of the kiln.
A glazed piece of china can be decorated with enamels, decals or precious metals. Some designs or aspects of the design must be done by hand, while others can be done by machine.