Ancient purple

On the other hand, the almost colorless fluid secreted by Murex brandaris, a shellfish of the Mediterranean Sea region, becomes reddish purple on contact with air. The fluid was used by the Phoenicians as a dye from about 1500 BC, and the purple dye is known as Tyrian purple, ancient purple, or shellfish purple, etc. Friedlander, in 1915, isolated about 1.5 g of the pigment from 12,000 specimens of M. brandaris, and clarified its chemical structure as 6,6 -dibromoindigo [5]. Subsequently, the origin of this pigment was identified as sodium tyrindoxyl sulfate [6]. 

When a question exists about whether the carving is ancient, an examination under uv illumination can be very helpful. For example, an aged marble surface exhibits, under a properly filtered mercury lamp, a mellow, brownish fluorescence, whereas a fresh surface, under the same conditions, appears purple. It is not uncommon that old carvings have been sharpened this is detectable with the microscope and under uv examination. 

Another ancient dye is the deep blue indigo [482-89-3], the presence of two bromine atoms at positions gives the dye Tyrian purple [19201 -53-7] once laboriously extracted from certain sea shells and worn by Roman emperors. 

Tyrian Purple was the most expensive and rare dye of the ancient world principally because only a small amount of dye could be obtained from each moUusk, roughly 0.12 mg (95). It was always considered a color of distinction and restricted to regal and ecclesiastical uses ia the Eastern Roman Empire, the heir to the throne at By2antium bore the proud name Porphjro-Genitur, bom to the purple. The Hebrews used purple ia many decorations of the Tabernacle (23). 

Ancient artisans were able to confer special colourings to their artefacts by applying particular techniques and treatments, which were lost in later centuries. They were also able to give copper based alloys the appearance of precious metals. Some of these special methods have been discovered and identified on ancient objects. The most famous of these alloys in Roman times was certainly Corinthian bronze, a copper alloy containing small amounts of precious metals, which acquired a purple-black or blue-black patination... 

Vat Dyes. Vat dyes are insoluble in water. Indigo, for example, an ancient blue dye, is probably the best-known example of an ancient vat dye others include woad and Tyrian purple. Since the process of dyeing requires that the dye be in solution, dyeing with a vat dye (or vat dyeing, as the process is known) is possible only after the vat dye has been made soluble by a relatively long and somewhat complicated chemical procedure. The terms vat dye and vat dyeing are probably derived from the large tanks or "vats", in which the process was carried out in ancient times. 

Berke, H. (2007), The invention of blue and purple pigments in ancient times, Chem. Soc. Rev. 36, 15-30. 

Berke, H. (2002), Chemistry in ancient times The development of blue and purple pigments, Angewandte Chemie. Int. Ed. 41(14), 2483-2487. 

Doumet, J. (1980), A Study on the Ancient Purple Color, Imprimerie Catholique, Beirut. 

Michel, R. H. and P. E. McGovern (1990), The chemical processing of royal purple dye Ancient descriptions as elucidated by modem science, ArchaeoMaterials 4, 97-104. 

Debromination with ageing has been observed in the indigoid components of purple [171,172], and photochemical breakdown patterns of the three anthocyanidins contained in Arrabidaea chica red dye, produced by Andean Indian cultures in the tenth to fifteenth centuries, have been hypothesized [173]. Although identifying dye sources in ancient artefacts is quite difficult, it is helped considerably by understanding the fading and degradation mechanisms. 

Suddenly tired, you make your way to the purple-draped bed and stretch out upon it. The Grail gleams, the stars shine overhead, the scarlet priestess sings the ancient songs, and you fall asleep. You dream a dream—a vision within a vision. Remember. 

Another early use of iron oxides was as a cosmetic. The cosmetic boxes (cockleshells) found in the Royal Cemetery in the ancient Sumerian city of Ur contained a range of different colours. XRD analysis by the Research Department of the British Museum showed that the principal components of the red and yellow colours were hematite and goethite, respectively (Bimson, 1980). One box also contained a purple powder consisting of a mixture of quartz grains and large crystals of hematite. 

Technological compounds and laboratory tools The technological use of natural products is as old as humanity, although mixtures of unknown conqjosition were mostly used before the advent of chemistry. Mummification in ancient Egypt is one such exan le. In contrast, that of the Phoenician Tyrian Purple was an advanced technology based on a practically pure substance. 

---