vocabulary lesson

I do not often put up interesting words, but I figure today’s is worth it – you know how in certain woods and gems, it appears as though there are many deep layers of material that cause the surface of the object in question to shimmern and almost glow? Tiger Eye stones have it, and really good ironwoods have it. Well, that beautiful shimmer (which, personally, I have always liked) is referred to as “chatoyancy“:

In gemology, chatoyancy, or chatoyance, is an optical reflectance effect seen in certain gemstones. Coined from the French “œil de chat,” meaning “cat’s eye,” chatoyancy arises either from the fibrous structure of a material, as in tiger eye quartz, or from fibrous inclusions or cavities within the stone, as in cat’s eye chrysoberyl. The effect can be likened to the sheen off a spool of silk: The luminous streak of reflected light is always perpendicular to the direction of the fibres. For a gemstone to show this effect best it must be cut en cabochon, with the fibers or fibrous structures parallel to the base of the finished stone. Faceted stones are less likely to show the effect well.

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Chatoyancy can also be used to refer to a similar effect in woodworking, where certain finishes will cause the wood grain to achieve a striking three-dimensional appearance.

Well, whatever you call it, I have always found that shimmer particularly attractive…. so I guess it figures that woods displaying it tend to be more than a little expensive…