[5] It was used in antiquity as a blue pigment to color a variety of different media such as stone, wood, plaster, papyrus, and canvas, and in the production of numerous objects, including cylinder seals, beads, scarabs, inlays, pots, and statuettes.

The earliest evidence for the use of Egyptian blue, identified by Egyptologist Lorelei H. Corcoran of The University of Memphis, is on an alabaster bowl dated to the late pre-dynastic period or Naqada III (circa 3250 BC), excavated at Hierakonpolis, and now in the Museum of Fine Arts, Boston.

[10] He refers to it as caeruleum and describes in his work De architectura how it was produced by grinding sand, copper, and natron, and heating the mixture, shaped into small balls, in a furnace.

Finally, only at the beginning of the nineteenth century was interest renewed in learning more about its manufacture when it was investigated by Humphry Davy in 1815,[12] and others such as W. T. Russell and F. Fouqué.

Following a number of experiments, Tite et al. concluded that for fine-textured Egyptian blue, two stages were necessary to obtain uniformly interspersed crystals.

Coarse Egyptian blue was relatively thick in form, due to the large clusters of crystals which adhere to the unreacted quartz.

[16] It is believed that calcium oxide was not added intentionally on its own during the manufacture of Egyptian blue, but introduced as an impurity in the quartz sand and alkali.

However, analysis by Jaksch et al. of various samples of Egyptian blue identified variable amounts of phosphorus (up to 2 wt %), suggesting the alkali source used was in actuality plant ash and not natron.

Recent excavations at the same site uncovered a large copper-based industry, with several associated crafts, namely bronze-casting, red-glass making, faience production, and Egyptian blue.

Egyptian blue was found in Western Asia during the middle of third millennium BC in the form of small artifacts and inlays, but not as a pigment.

[22] Around the turn of the eras, Roman sources report that a certain Vestorius transferred the production technology from Alexandria to Pozzuoli near Naples (Campania, Southern Italy).

[24] In fact, archaeological evidences confirm production sites in the northern Phlegraean Fields and seem to indicate a monopoly in the manufacture and trade of pigment spheres.

Inclusion of knowledge from neighbouring disciplines made possible to read out the information about the type and provenance of the raw materials, synthesis and application of the pigment and ageing of the paint layer preserved in the previously not accessible trace components, and thus to reconstruct the individual "biography" of the Egyptian blue from St. Peter.

This paradigm shift in the research history of Egyptian blue provided natural scientific evidences for the production in the northern Phlegraean fields (agreement with trace minerals found in the beach sands at the Gulf of Gaeta), the use of a sulphidic copper ore (instead of often-mentioned metallic copper or bronze), and plant ash as flux in the raw material mixture.

Furthermore, indications for a synthesis predominated by solid state reactions were found, while the melting of the raw materials into glass most likely played a negligible role.

[23] A follow-up study on Roman Imperial pigment balls excavated in Aventicum and Augusta Raurica (Switzerland; first to third century AD) confirmed the results in 2022.

The consistent composition of around 40 identified minerals establishes a connection to the northern Phlegraean Fields; a sulphidic copper ore and plant ash have also left their marks.

In addition, the analyses revealed unwanted by-products of the synthesis, locally limited to microparticles on the sphere's surfaces, which can be traced back to suboptimal burning times or mixing ratios, respectively: a cuprorivaite with crystal defects in its layer structure and a copper-bearing green glass phase, characterised by Raman spectroscopy for the first time.

[25] Egyptian blue's extremely powerful and long-lived infrared luminescence under visible light has enabled its presence to be detected on objects which appear unpainted to the human eye.

[26] This property has also been used to identify traces of the pigment on paintings produced as late as the sixteenth century, long after its use was presumed to have died out.

[27] The luminescence in the near-infrared, where neither fat nor hemoglobin show high absorption coefficients, in conjunction with the capacity of Egyptian blue to delaminate by splitting into nanosheets after immersion in water, also indicates it may have several high-technology applications, such as in biomedicine (e.g. bioimaging), telecommunications, laser technology, and security inks.

This suggests that Egyptian blue pigment could be used in construction materials designed to cool rooftops and walls in sunny climates, and for tinting glass to improve photovoltaic cell performance.