I read with interest your article on determining the origin of emeralds by measuring oxygen isotopes. While there is great potential for legal and historical applications, I think that using this method to determine the source of gems for purely economic reasons is ludicrous. At least for myself, whether an emerald originated in Austria or Columbia would be of less importance than its intrinsic beauty. And from experience managing a jewelry store, I can state that most of my customers would react the same way.

RuthAnn Nichols
Champaign, Ill.

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