DIAMOND AND DIAMOND GRADING

Abrasion (Abr) - Answer-A series of minute nicks along the facet junctions of a fashioned diamond; gives the edges a white or fuzzy appearance. (Assignment 10) Adamantine luster - Answer-The highest degree of luster possible in a transparent material. (Assignment 8) Aggregate - Answer-A solid mass of individual, randomly oriented crystals, intergrown or held together by a natural binding agent. (Assignment 7) Alluvial deposit - Answer-A deposit where gems are eroded from their source rock, then transported away from the source and further concentrated. (Assignment 5) Angle of incidence - Answer-The angle at which a ray of light strikes a surface, measured from the normal. (Assignment 8) Angle of reflection - Answer-The angle between the normal and a reflected ray of light. (Assignment 8) Annealing - Answer-Using heat to stabilize irradiated color in gemstones. (Assignment 12) Appraisal - Answer-An estimation of the value of an article, usually for insurance purposes. (Assignment 1) Average girdle diameter - Answer-The result achieved by adding the smallest and largest girdle measurements of a round brilliant and dividing by two. (Assignment 14) Bast - Answer-Frosted rough diamond. "Bark" in Dutch. (Assignment 9) Bearded Girdle (BG) - Answer-Very small feathers that extend from the girdle surface into the stone; can result from the cutting process. (Assignment 10)