cobalt blue spinel

  • Describing Color in Gems • A Fool's Guide • Lotus Gemology

    A Fool's Guide to Color in Gems

    Color types such as "pigeon's blood," "Paraíba" and "cobalt blue" have become wildly popular in the gem trade. But there is a vast difference between coining such terms and applying them in a way that is both consistent and logical. Richard Hughes casts a critical eye at the subject.

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