Egyptian blue

Egyptian blue is a blue, artificial, inorganic mineral pigment. In the main mineral phase is Cuprorivait ().

Neuzeitliche Synonyms: Blue frit frits Blue, Pompeijanisch blue, copper blue, Kupferfritte. Kyanos (Greek ) and caeruleum (Latin ) are ancient names for the color blue. In Egypt, this pigment is now called Blue Nile. The coloring mineral called Cuprorivait.

Features

Egyptian blue is a coarsely crystalline pigment (particle size 80 microns ) of neutral blue, strong colors. Typically is caused by the structure schichtsilikatische " glitter ". Finely ground varieties (grain sizes less than 50 microns ) bright on strong.

In 2013 it was found that the pigment very easily disintegrates into extremely thin layers ( nanosheets ). In addition, these layers would make when excited by light for a long time a strong radiation in the near-infrared range, which makes the material for applications in biomedical imaging, for light emitting devices or for safety technology interesting.

Production

Prepared from the substance- forming elements silicon and calcium, the copper coloring and melting point lowering sodium or potassium as a flux. These finely ground quartz sand and limestone were mixed with copper or bronze chips and some soda or salt vegetable ash and burned at least 870 ° C for several hours. It is important that the ratio of copper to calcium is approximately 1:1, because only then creates the crystalline layer silicate Cuprorivait (), the chromophoric component of Egyptian Blue pigment. In nature Cuprorivait occurs only very rarely. So far, it has been demonstrated in small amounts only in Vesuvlava.

History

Egyptian blue is one of the oldest man-made color pigments. A use in ancient Egypt since the 4th Dynasty ( 2639-2504 BC) is occupied by Lucas & Harris. The discovery of the pigment was probably closely related to the earlier production of colored glazed ceramics ( Egyptian faience ), since this same raw materials were used.

Egyptian blue was used by almost all subsequent dynasties. Exceptions are found in the politically turbulent intermediate times, where mixtures of carbon black and white were detected as blue pigment. In ancient times, Egyptian blue to Mesopotamia, Greece and the Roman Empire and its provinces spread.

2009 could be detected using a highly sensitive method to some sculptures of the Elgin Marbles traces of pigment. For some time, researchers suspect that today, resplendent in pure white marble Parthenon was originally painted at least partly, as evidenced by this discovery can be taken for granted now.