DDG Ass #9 Key Terms & Concepts PDF

DDG ASS #9: Key Terms and Concepts Blemish—Clarity characteristic confined to the surface of a polished gemstone. Brightfield Illumination—Lighting a diamond from below to create a bright background. Clarity Characteristic—Internal or external feature of a gemstone that helps determine its...

DDG ASS #9: Key Terms and Concepts Blemish—Clarity characteristic confined to the surface of a polished gemstone. Brightfield Illumination—Lighting a diamond from below to create a bright background. Clarity Characteristic—Internal or external feature of a gemstone that helps determine its quality and establish its identity. Darkfield Illumination—Lighting a diamond from the side against a black non-reflective background. Depth of Field—The distance that’s clear and sharp above and below a point you focus on with a magnifier. Feather—A trade term for any break in a diamond. Flash Effect—A flash of changing color seen in a fracture-filled diamond when you look parallel to the filled inclusion and rock the diamond back and forth under magnification. Fracture Filling—Treatment that involves injecting a molten glass substance into a diamond’s surface- reaching feathers or laser drill-holes. Inclusion—Clarity characteristic totally enclosed in a polished gemstone or extending into it from the surface. Key Concepts: Clarity grading is one of the most important aspects of the GIA Diamond Grading System. Clarity characteristics determine a stone’s clarity grade, help set its value, and help identify it. Your first impression of a diamond’s face-up appearance should strongly influence its clarity grade. A good-quality triplet loupe for diamond grading contains lenses for magnification, color, and linear distortion correction. Use abbreviations to note inclusions and blemishes. You must disclose the presence of laser drilling. A natural can be considered a sign of efficient cutting.