Cobalt blue color pegmint portable#

The synthesized pigments presented good chemical and thermal stability, high tinting strength. Comparing with pure CoAl 2O 4 pigments, the cobalt content of hybrid pigments was lower, but its blue components (− b *) were exceeded to 40 when the Co/Al mole ratio reached up to above 0.10, which was closed to that of the commercial cobalt blue pigments. With the increasing Co/Al mole ratio, the CoAl 2O 4 spinel contents in the hybrid pigments increased, and the blue components (− b *) of the pigments were elevated. Results showed that the hybrid pigments were consisted of the CoAl 2O 4 spinel and Al 2O 3 corundum, and the CoAl 2O 4 spinel evenly covered on the surface of Al 2O 3 corundum. The structure and properties of the synthesized pigments were characterized by XRD, SEM, EDX, UV–Vis spectroscopy and colorimetry. It is suggested that the exhaustion of native silver and siliceous silver ore deposits during the Bronze Age, with argentiferous lead ores becoming the main source of silver, depleted the amount of cobalt available, thereby reducing the amount of glass produced which, in turn, led to increases in recycling during the New Kingdom period.The CoAl 2O 4/Al 2O 3 hybrid pigments with low cobalt content were prepared by heterogeneous chemical precipitation and calcination methods. Treating the cobalt-blue colourant as a slag composed of the gangue of a smelting system provides an explanation for the unique elevated levels of alumina and lower levels of potash found in cobalt-blue glasses, as well as providing an explanation for the cessation of cobalt exploitation at the end of the Late Bronze Age. Experiments conducted on ore containing cobalt-nickel arsenides with native silver demonstrate that not only can silver be extracted and that concentrated cobalt glass can be produced simply by adding a flux, but that some components of the ore partition preferentially into the silver or the glass slag, thereby weakening their associations with the other components in archaeological glass. Re-analysis of the compositions of cobalt-blue glass frit found at Amarna, as well as Egyptian and Mesopotamian glass, suggests that the cobalt colourant was a byproduct of silver extraction from these ores and can therefore be considered as a concentrated cobalt glass slag, which travelled in the form of a frit to glass producers who added it to locally derived base glasses and/or their precursors. It is further proposed, however, that the generally accepted cobalt source for Egyptian glass was not the alum deposits of Egypt's Western Desert, but derived from cobaltiferous siliceous ores, possibly from central Iran. It is shown in the current article that some of this 18th Dynasty glass and the majority of the 19th-20th Dynasty glass had been recycled, not only supporting the general consensus that glass production virtually disappeared by 1250 BC, but that the cobalt source did not necessarily change. This result suggests that a new cobalt source other than cobaltiferous alum from the Western Oases was utilized in Egypt during the Ramesside Period.Ī recent compositional study of Egyptian cobalt-blue glass from museum collections in Japan (18th Dynasty) and from the site of Dahshur (18th and 19th- 20th Dynasties) concluded that a new source of cobalt was exploited for the later Dahshur glass, thereby suggesting that glass production continued into the Ramesside period (Abe et al. This method revealed that the compositional characteristics of the cobalt-blue colorant in these Ramesside glasses and faiences is different from the colorant derived from cobaltiferous alum used in the 18th Dynasty, based on the comparison of transition metal composition and alumina content with those of the cobalt blue-colored artifacts from the 18th Dynasty.

Cobalt blue color pegmint portable#

In this study, we brought a portable X-ray fluorescence spectrometer to two archaeological sites located in the Memphite region and used it for onsite analyses of Ramesside cobalt blue-colored glasses and faiences.

There is little evidence of the production of cobaltblue glass in the Ramesside Period (the 19th-20th Dynasties) in the New Kingdom of Egypt.

The use of this alum, especially in glass, was suddenly limited at the end of the 18th Dynasty. The source of this cobalt was cobaltiferous alum from the Western Oases of Egypt. Cobalt-blue colorant was first used in the 18th Dynasty in the New Kingdom of Egypt.