Bone China v Porcelain

Bone china is a type of soft-paste porcelain that is composed of bone ash, feldspathic material, and kaolin. It has been defined as ware with a translucent body containing a minimum of 30% of phosphate derived from animal bone and calculated calcium phosphate. Developed by English potter Josiah Spode, bone china is known for its high levels of whiteness and translucency, and very high mechanical strength and chip resistance. Its high strength allows it to be produced in thinner cross-sections than other types of porcelain.

From its initial development and up to the later part of the twentieth century, bone china was almost exclusively an English product, with production being effectively localised in Stoke-on-Trent. Most major English firms made it, including Mintons, Coalport, Davenport, Royal Crown Derby, Royal Doulton, Hereford Fine China, Wedgwood and Royal Worcester.

The production of bone china is similar to porcelain, except more care is needed because of its lower plasticity and a narrower verification range. The traditional formulation for bone china is about 25% kaolin, 25% Cornish stone and 50% bone ash. The bone ash that is used in bone china is made from cattle bones that have a lower iron content. These bones are crushed before being degelatinised and then calcined at up to 1250°C to produce bone ash. The ash is milled to a fine particle size.  The kaolin component of the body is needed to give the unfired body plasticity which allows articles to be shaped. This mixture is then fired at around 1200°C.  The raw materials for bone china are comparatively expensive, and the production is labor-intensive, which is why bone china maintains a luxury status and high pricing.

Porcelain (also known as china or fine china) is a ceramic material made by heating materials, generally including clay in the form of kaolin, in a kiln to temperatures between 1,200 and 1,400 °C (2,200 and 2,600 °F). The toughness, strength, and translucence of porcelain arises mainly from the formation of glass and the mineral mullite within the fired body at these high temperatures.

Porcelain derives its present name from the old Italian porcellana (cowrie shell) because of its resemblance to the translucent surface of the shell. Porcelain can informally be referred to as "china" or "fine china" in some English-speaking countries, as China was the birthplace of porcelain making. Properties associated with porcelain include low permeability and elasticity; considerable strength, hardness, toughness, whiteness, translucency and resonance; and a high resistance to chemical attack and thermal shock.

  The most common uses of porcelain are for utilitarian wares and artistic objects. It can be difficult to distinguish between stoneware and porcelain because this depends upon how the terms are defined. A useful working definition of porcelain might include a broad range of ceramic wares, including some that could be classified as a stoneware. Porcelain is used to make household wares, decorative items and objects of fine art amongst other things.

 

  

 

Bone China v Porcelain

In A Nutshell

Bone china, fine china, porcelain: They can look very similar, but there’s a definite difference in what they’re made from. Bone china is, as its name suggests, made from bone—cow bone in particular, although in rare cases you could be eating off of a plate made from a dead person. The same manufacturing processes are used in making fine china, but without the bone content. Porcelain is also created in much the same way, but it’s fired at a higher temperature and the end result is much harder.

The Whole Bushel

Bone china is, as its name suggests, made from cow bone. The bone is finely ground into bone ash, and it is then mixed with feldspar, ball clay, quartz, and kaolin (a type of clay). The quality of the finished product is based on how much bone is in the mixture; a high-quality bone china should contain at least 30 percent bone and can go as high as 40–45 percent.
Porcelain has been around since around A.D. 620; more modern methods and mixtures started to be used around A.D. 1279. Originating in China, the earliest porcelains used kaolin (a type of clay) and pegmatite (a type of granite). Early European versions used clay and ground glass. In 1707, German manufacturers started using feldspar instead of glass in a process that continues today. In today’s porcelain, silica is also added to the raw ingredients. The raw materials are finely ground, cleaned, formed in a mold, and then fired.

The firing process is what creates either porcelain or fine china. If the temperature is high—around 1,455° Celsius (2,650° F)—the finished product is much more durable and is known as porcelain. If it’s fired at a lower temperature—around 1,200° (2,200° F)—it’s known as fine china. Fine china is much softer than porcelain, making it much more suitable for applications such as plates and cups. Porcelain is strong enough and durable enough that it’s suitable for a wide range of industrial applications such as electrical insulators.

Bone china undergoes two firing processes. The first causes the product to shrink, and about 20% of the pieces that are made will crack and break at this stage. The second firing happens after the piece is glazed, and melts the glaze into the piece. Those that don’t crack or break during this stage are then decorated with their final patterns. Many pieces are hand painted or sprayed, though in some cases decals can also be applied.

At a glance, it’s easy to tell the difference between bone china and fine china if you know what you’re looking for. The addition of bone ash gives bone china a warm color, while fine china will be a brighter white. If you hold the china up to the light, you’ll see that bone china has a translucent quality compared to fine china. Porcelain is a much more durable material, and is much harder than either type of china.

But then there’s the creepier side of china. American artist Charles Krafft has found that it doesn’t have to be cow bone that’s used for the bone component in bone china. The current mixture used for British bone china was created by a man named Josiah Spode (Spode is still a major manufacturer of bone china in the UK), and Krafft decided to simply swap out the cow bone ash in Spode’s recipe for human bone ash, retrieved from a crematorium and finely milled. Calling his new product “SPONE,” you can still commission him to create a special memento made of your loved ones.






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