Egyptian blue is a pigment that was invented over 4,500 years ago. It became popular throughout the Roman Empire, and it is the first synthetic pigment in history. It dates back to the Fourth Dynasty and was used until the end of the Roman era. In ancient civilisations, the blue pigment was rare and expensive. It was made originally out of natural minerals such as lapis lazuli, which were ground into a powder that came from Afghanistan. The ancient Egyptians held the colour blue in very high regard and considered it crucial for their paintings as it was the colour of the sky and the Nile. Additionally, it symbolised creation, the universe, and fertility. Hence, they started manufacturing Egyptian blue pigment to meet their high demand.

The ancient Egyptians used blue pigment to paint on many materials such as papyrus, stone, wood, and canvas, for multiple purposes. They used it for painting walls, ceilings, and statues, as well as creating glazes for pottery. They called this invention the artificial lapis lazuli. Egyptologist Lorelei H. Corcoran discovered the first product that had Egyptian blue incorporated from the pre-dynastic era — an alabaster bowl which is being exhibited at the Museum of Fine Arts, Boston, and dates back to around 3250 BC.

The composition of the Egyptian blue pigment

The manufacturing technique and components of Egyptian blue were forgotten as its use ended with the fall of the Roman Empire. The unique historical source that mentioned the ingredients and the process of creating Egyptian blue dates to the first century BC, by the Roman writer Vitruvius in his book De Architectura. He wrote that the colour was created by mixing sand, copper, and natron. Then, the components were mixed and rolled into small balls before being placed in clay pots and heated for many hours at temperatures between 800 and 1,000 °C. After that, the mixture was ground to get the pigment and to create the paint.

Scientists can now test the pigment with modern technology techniques, discover how it was composed and used in the past, and find out how it can be incorporated into modern technology. The experiments proved that they mixed natron, sand, and minerals called azurite — the chemical name for this mixture is calcium copper silicate.

The complex process of manufacturing Egyptian blue was an impressive achievement that demonstrated the competence of the ancient Egyptian chemists. The main challenge was having the ability to produce a pigment which required careful control of this high temperature. On top of that, Egyptian blue preserved its properties, and its chemical composition remained almost the same in most artefacts for nearly 3000 years.

Present-day uses

Archaeologists conducted many experiments on the existing Egyptian antiques that have this pigment. They discovered that exposing Egyptian blue to red light reflects infrared light, which can be detected using modern technology. Because of its intense luminescence, even in the absence of any visible blue hue, a small amount of its pigment can be discovered with cameras or other electronic devices.

Researchers have also found multiple uses for Egyptian blue that can be beneficial in day-to-day living. Since the human body can absorb infrared light, studies have shown that the pigment's molecules can improve medical imaging methods through the use of a dye. The pigment absorbs natural light; hence, it can be integrated into producing building materials to reduce the temperature of buildings in countries with warmer climates. It can also be used to improve the effectiveness of solar cells. Furthermore, Egyptian blue can be utilized in manufacturing security ink for official documents to prevent forgery. It too can be used in high-technology applications such as telecommunications and laser technology.