diamond

  • Colored Stone Grading | A Heretic's Guide

    Colored Stone Grading • A Heretic's Guide

    Developing a comprehensive colored stone grading system has been the dream of gemologists since the late 1970's, but despite a number of valient attempts, we are no closer to the goal today than we were four decades ago. This article examines the various problems of colored stone grading, explaining why the challenges are at least an order of magnitude greater than the grading of diamonds.

  • Fiber-Optic Light in Gemology | Living in the Dark Ages

    Fiber-Optic Light in Gemology • Living in the Dark Ages

    The role of fiber-optic lighting in gemological microscopy.