Chapter 9 Key Concepts & Key Terms Flashcards
What is one of the most important aspects of the GIA Diamond Grading System?
Clarity grading
Clarity grading determines a stone’s clarity grade, value, and identification.
What should strongly influence the clarity grade of a diamond?
First impression of a diamond’s face-up appearance
This impression is crucial in assessing clarity.
What type of loupe is recommended for diamond grading?
Good-quality triplet loupe
Contains lenses for magnification, color, and linear distortion correction.
What must you disclose regarding diamond treatment?
Presence of laser drilling
This is important for transparent grading.
What can a natural in a diamond indicate?
Efficient cutting
It can be seen as a positive clarity characteristic.
Define ‘Blemish’ in diamond grading.
Clarity characteristic confined to the surface of a polished gemstone
Blemishes affect the external appearance.
What is Brightfield illumination?
Lighting a diamond from below to create a bright background
This technique helps in evaluating clarity.
What is a Clarity characteristic?
Internal or external feature of a gemstone that helps determine its quality and establish its identity
These characteristics are key in grading.
Define ‘Darkfield illumination’.
Lighting a diamond from the side against a black non-reflective background
This method highlights inclusions and blemishes.
What does ‘Depth of field’ refer to?
The distance that’s clear and sharp above and below a point you focus on with a magnifier
Important in evaluating the clarity of inclusions.
What is a ‘Feather’ in diamond terminology?
A trade term for any break in a diamond
Feathers can impact the clarity grade.
What is the ‘Flash effect’?
A flash of changing color seen in a fracture-filled diamond when viewed parallel to the filled inclusion
This effect occurs when the diamond is rocked back and forth under magnification.
What does ‘Fracture filling’ involve?
Injecting a molten glass substance into a diamond’s surface-reaching feathers or laser drill-holes
This treatment aims to improve the appearance of the diamond.
Define ‘Inclusion’ in the context of diamonds.
Clarity characteristic totally enclosed in a polished gemstone or extending into it from the surface
Inclusions can significantly affect the clarity grade.
