Glass, ancient, colorants

Ancient colored glasses contained nanoparticles of Au and Cu. How were these synthesized i.e., what metal salts were used, along with other experimental conditions required to yield nanosized metal clusters) ... 

Glass-paste coloring may be considered as one of the most ancient decorations, yet limited essentially to the blue and green colors. Nowadays, more than 14,000 shades are possibly used. 

After the discovery of phosphorus, 66 years passed before another new element, cobalt, was discovered. Cobalt compounds were known since ancient times and had been used to color glass since the sixteenth century. They were collectively known under the name kobold. Miners believed that the presence of these substances in mines was the work of malicious gnomes called kobolds, who wanted to poison the miners. 

Cobalt has been in use as a coloring agent for glass since ancient times. The metal was isolated by Brandt in 1735 and confirmed as an element by Bergman in 1780. Cobalt is widely distributed in nature, but in small concentrations. Its concentration in the earth s crust is estimated to be about 0.0025% and in the sea water is about 0.02 pg/L. Cobalt minerals with their chemical formula and CAS Registry numbers are tabulated below ... 

A. Lucas stated that antimony and its compounds were rarely used in ancient Egypt. He mentioned one example of a Nineteenth-Dynasty eye paint consisting of antimony sulfide the use in the same Dynasty of antimony and lead to color glass yellow some small beads of metallic antimony, probably made from native metal in the Twenty-second Dynasty (945-745 B.C.) a tablet of metallic antimony which M. Julius... 

The word crystal often meant with the ancients quartz crystal, but it is very evident that with the authors of these notes the term was used in a more comprehensive sense to include other transparent or translucent stones. This use is very evident in the many recipes for imitation of precious stones, where the processes involve a degree of porosity or absorbent power towards colored solutions not possessed either by quartz crystal or by glass, while certain agates, micas, alabasters or other stones possess this property. In case of the above recipe, it is doubtful whether any such mordanting would in a reasonable time roughen the surface of real quartz crystal adequately. The quicksilver here mentioned is evidently the same substance of pearly luster previously referred to. 

Powders containing bismuth compounds have long been used for decorative purposes to generate a shiny luster or lustrous colors (e.g., facial cosmetic powder in ancient Egypt, imitation pearls made by coating glass and ceramic beads). Bismuth oxychloride [7787-59-9], BiOCl, Mr 260.4, was the first synthetic nontoxic nacreous pigment. It is produced by hydrolysis of acidic bismuth solutions in the presence of chloride ions. Precipitation conditions may be varied (concentration, temperature,... 

All the ancient glasses were based on silica (sand), modified with considerable amounts of various metal oxides, mainly soda (Na20) and lime (CaO). This is still the most common glass being used today. It is known as soda lime glass. However, the ancient glass was usually colored and opaque due to the presence of various impurities, whereas most modem glass has the useful property of transparency. 

Colored Glass. The natural glasses used by the ancients were all dark in color, usually ranging from olive green or brown to jet black. The color was... 

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