Rock #5258Light refraction causes electric blue agate I have never seen anything quite like this before from The Carver Agate Field.  The presence of the sagenitic growth seen in this specimen no doubt is largely responsible for the electric blue color.  While the sagenitic golden material obviously is not blue, I believe that it captures certain wave lengths of light that enter the stone, while in this case leaving the blue light wave lengths to refract back out of the stone and make it appear deep blue.  The refraction of light by the internal characteristics of a stone is not unusual—think of diamonds and opals.  On page 27 of his book Gemstones of the World, 1977, Walter Schumann explains as follows: “color is produced by light;  light is electromagnetic vibrations at certain wave lengths.  This visible light falls into six parts, each of a particular color (the spectral colors: red, orange, […]

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