The blue color is one of the most beloved of all time, and a very special shade, the Egyptian blue, is considered particularly precious since the most ancient times.
In fact, in addition to being considered a regal color, associated with the sky, water source of life and divinity, the Egyptian blue is the oldest known artificial pigment.

The first dyes in art and craftsmanship 

The Egyptian blue seems to have spread since 3100 BC.

In fact, several other red, black, brown and other pigments were common long before the spread of Egyptian blue.

It was much easier to produce them because they were extracted from vegetables or obtained from minerals already present in nature.

For example, from the processing of a plant commonly known as Woad, it was obtained a shade of blue, much used in artistic and ritual representations.

But the most precious and sought-after blue pigment was azurite, a rare and therefore very expensive substance, derived from the mineral lapis lazuli.

The costs for its extraction and transformation were so high that the ancient Egyptians sought, and finally found, the way to artificially create their own blue pigment. 

A mysterious, complex and state-of-the-art procedure

In the last two centuries, scientists and archaeologists from all over the world have studied the composition of Egyptian blue, carrying out numerous experiments to discover the techniques used to produce it in antiquity.

For a long time this procedure remained a mystery, because no document of the time describes the method of production of Egyptian blue.

The only written evidence available is attributed to Vitruvius, a Roman historian of the first century BC, but is somewhat inaccurate. 

The first reliable sources on the raw materials and methods used by the ancient Egyptians to manufacture their blue pigment, were produced around 1960.

Today we know that they used a mixture with well-defined proportions of copper (in the form of filings or malachite), silica (ground quartz or desert sand) and limestone, heated to about 850-950 C.

To obtain a shade of more intense blue, the powder after cooking was remastered, kneaded with water, packaged in small balls and put again in the oven.

Ancient and modern uses of Egyptian blue

The result of this process is considered the first artificial production pigment in history.

In ancient times it was used to paint wooden furnishings, to decorate papyrus sheets, canvases, cloth garments, or to enamel vases and other objects, especially in the funerary field.

This is because in ancient times blue had a strong mystical and propitiatory meaning.

Today, in addition to being a very popular shade in fashion, design and art, the Blue Egyptian pigment has different uses in science and technology.

In fact, when exposed to a visible light source, it emits a very powerful and with a rather long decay time luminescence in the near infrared.

In addition, it can be very malleable to form nanosheets a few thousandths of a millimeter thick.

These features make Egyptian blue suitable for applications in biomedicine, telecommunications, thermal applications, photovoltaics, and others.