What is Bone China Made of? & How is Bone China Made?

Whether for practical use or aesthetic appeal, bone china is considered to be one of the most refined and sophisticated tableware products. Since being developed in 18th Century England, bone china has established its reputation as a fine addition to any home.

Well crafted bone china is fine and delicate, yet durable. It is carefully created through a mixture of bone ash and other high-quality materials, making it a product that is set to endure. Because of this, bone china is valued as one of the world’s most beautiful ceramics.

Introduction to Bone China

Bone china is generally characterized by its translucency and overall sophistication. The superior characteristics of bone china can include:

Warm, creamy white color
High degree of translucency
Delicate and elegant shape
High durability
Unsurpassed luster
Beautiful coloring of design

However, this will vary on the manufacturer and the techniques they use.

What is Bone China Made of?

Bone Ash

Bone ash was first used by the English potter Thomas Frye in 1748. The use of bone ash has many advantageous mechanical and thermal properties, lending itself to being a popular material used in tableware worldwide.

The creation of bone ash involves a lot of nitty gritty and sometimes complicated details. In short, bones are calcined and heated, then ground down into bone ash, which contains calcium, phosphorus, and oxygen.

The definition of bone china is usually stipulated in the amount of calcium phosphate. In the United Kingdom, bone china wields more than 35% of calcium phosphate, whereas in the United States, bone china contains only around 25%.

Feldspar

Feldspar is often deemed the backbone of the ceramic and porcelain industry. In the manufacture of ceramics, it is one of the most crucial ingredients.

The feldspar mineral is rich in the earth’s crust. Feldspar is primarily used for its alumina and alkali content, crucial in the creation of ceramics. It cements the crystalline phase of other ingredients in the ceramic.

Feldspar does not have a strict melting point, but instead melts gradually over a range of temperatures. Feldspars can improve the overall strength and durability of a ceramic, ensuring that it is consistently usable and lasts for a very long time.

Kaolin

Kaolin, also called China Clay, is a major ingredient of bone china. It is said that Kaolin was first sampled in a place called Kaoling in China when the Chinese exemplified its use in the manufacture of porcelain.

Kaolinite is the primary mineral of kaolin. In its natural state, it is a white, soft powder consisting of small platy crystals which are unable to be seen by the naked eye.

Kaolin’s high fusion temperature and white burning characteristics make it an essential part in bone china’s beauty.

Clay

Bone china most often includes ball clays, which are kaolinitic sedimentary clays.

They are fine-grained and plastic in nature, giving bone china its white porcelain appeal and extra touch of strength and translucency.

The ball clay also makes the material easily molded to produce a range of aesthetic tableware.

How does Bone China Differ from that of Porcelain?

Bone china and porcelain have a similar backstory, minus the addition of bone ash to porcelain products.

Bone ash has proved to be a popular material, with its ability to enhance the strength of tableware by making it less brittle, and less likely to break than porcelain. Impact strength varies by shape, but bone china tends to be of a higher strength than porcelain.

This gives bone china its lightweight and delicate nature, making it a sophisticated and refined addition to any dining table.

How did Bone China Originate?

The production of bone china began in Europe. The history of how bone china was made starts with porcelain. While there is some debate about when China developed porcelain, experts believe they were made as early as 1000. By the 1600s they were being imported into Europe. The items were much sought after among Europeans, with it being regarded as enchanting and dream-like.

After being in awe of its beauty, European artisans tried to recreate the porcelain products, but were unable to find the right materials. An English potter discovered that bone ash could make white porcelain — which started the manufacturing of bone china in Europe in the early 1700s.

How is Bone China Made?

Depending on the manufacturer, there will be several steps required to make bone china. Below, we reveal the steps involved in bone china’s careful creation.

Step 1: Blending Raw Materials

Firstly, the bone ash that is calcium phosphate has raw materials like clay, feldspar and kaolin added to it. These raw materials are then blended at a high speed to be pulverized.

The higher percentage of bone ash present, the more white and translucent it is — resulting in a beautiful, bright product.

Step 2: Forming

Once the compounds have been grinded together (which can take up to 24 hours+), the batch is sieved to identify and eliminate impurities. Then, the raw materials are filtered and kneaded in a vacuum as air bubbles are removed. Automated jiggering is then performed by the turning mold and rollers. Materials, including large quantities of bone ash are difficult to shape at this stage as they are non-adhesive.

At this point, different manufacturers will employ special techniques to shape and divide the “slip.” The slip is the final mix that is left in a liquid state. Some may craft complex shapes through a slip casting method where liquid raw materials are poured into the mold. Others may use a big slicer to divide the slip up into separate discs.

Step 3: Bisque Firing

Through bisque firing, bone-dry clay is transformed from its fragile state to its durable ceramic one.

This is the process which allows safe decorating and glazing of the china – the clay receives life from the firing.

High temperatures shrink the product up to 20% of the original size, resulting in a close-to-finished product.

Step 4: Glazing

Next, a liquid glaze is blown evenly over the surface of the material, creating the signature glossy shine seen on most bone china products.

Apart from making it look beautiful, the glaze helps to form a protective outer layer to enhance the strength of the china. The glaze can either be applied by machine or hand dipping.

Step 5: Decorating

Decorative patterns can then be transferred by hand one at a time to each product.

Through gentle and skillful movements, colorful patterns emerge on the bone china.

This gives bone china a new brilliance, and these decals can be applied by hand or machine. Common decorative methods include hand painting, gold finishing, and spraying.

Step 6: Finishing

After decoration is applied to the bone china, it is fired again (or twice) to burnish the product. Firing is done twice to designs that have both decal and gold finishing, as the firing temperature of both types of finishings need to be different.

The product is then carefully packaged and depending on the manufacturer, will undergo rigorous quality checks.

The products are then finally sent out and enjoyed by customers around the world.

Visit NARUMI Today

At NARUMI, we take pride in our ability to deliver high quality, fine products to each and every one of our customers.

Our premium-quality bone china contains more than 40% bone ash giving it an optimal milky texture and lightweight feel.

Visit our website today to browse our wide range of sophisticated tableware.