Color for Fun and Enjoyment

Who among us does not enjoy the vision of a rainbow The spectral colors spread out across the sky inspire awe and pleasure no matter how many times we see them. For this reason, we have attempted to replicate rainbows artificially. We can go to any toyshop and find rainbow glasses, any rock shop and find rainbow quartz made by plasma ionization techniques. Jewelry and craft shops sell rainbow jewelry made by electroplating titanium or niobium oxide. Teachers use rainbow tubes with a universal indicator to demonstrate pH changes and acid-base reactions. Dye mixtures can be separated by rainbow electrophoresis and rainbow chromatography. Rainbow thermometers and toys are made from liquid crystals. Thermochromic materials can be heated to produce rainbow colors. Every toy shop is awash with rainbow colors, a phenomenon not available prior to the many inventions of the twentieth century [39]. 

It is not clear from the archaeological record if such colors were available for fun and pleasure in ancient times. The oldest known toy was a doll, with the yo-yo coming in a close second, but the coloring matter applied to these artifacts has not survived. What we do know from gravesites is that colored precious and semiprecious stones were an important part of human life and over the centuries, the joy of the color they impart has not abated. We see this joy in the face of a person enthralled by a beautiful amethyst, emerald, or diamond. 

As the prerogative of royalty, purple has created a mystique for amethyst that elevated it above other types of quartz crystals. Coveted by Catherine the Great and embedded in the British Crown Jewels, amethyst was once considered a 

Toward the end of his life, Berthelot (1827-1907) was able to show that amethyst, on heating, became colorless, but that the color could be restored by exposition to radium radiation [41]. Crystallographers today have discovered that color centers, structural flaws in the crystal lattice, are responsible for trapping or releasing energized electrons which can change the valencies of the interstitial iron impurities, thus yielding the colors. 

What is the most famous diamond in the world What is the most visited piece of artwork apart from the Mona Lisa To what diamond was attributed the curse that brought about the executions of Louis XVI and Marie Antoinette What diamond appreciated over 100 times its original valuation during the course of the twentieth century What diamond was donated by Harry Winston to the Smithsonian National Museum of Natural History What diamond contains boron impurities within its carbon lattice that confers on it a deep blue color, its 

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