Chapter 13 - Key Concepts & Terms Flashcards
What makes a significant contribution to a diamond’s brightness and fire?
A diamond’s pavilion
The pavilion is the lower portion of the diamond that affects how light interacts with it.
How is a diamond’s pavilion depth percentage typically evaluated?
Usually accurate enough for grading and appraising
This percentage helps assess the diamond’s overall quality.
What is generally true about the pavilion depth percentage and pavilion angle?
The greater the pavilion depth percentage, the steeper the pavilion angle
This relationship affects the diamond’s light performance.
What is the purpose of a culet in a diamond?
To prevent abrasion and chipping on loose diamonds
The culet is the small facet at the bottom of the diamond.
Why is including design and craftsmanship in the cut grade important?
It gives a well-crafted diamond the recognition it deserves
This acknowledges the artistry involved in diamond cutting.
What type of diamonds represent poor value due to their appearance?
Diamonds with thick girdles, steep crowns, or deep pavilions
They appear smaller face-up than their weights suggest.
What effect can poor polish have on a diamond?
It can make a diamond look dull and hazy
Even diamonds with the best proportions can suffer from this issue.
Do most diamonds have symmetry variations?
Yes, but the variations rarely affect appearance
This indicates that some flaws are not visually significant.
Which factors play the biggest role in determining a round brilliant diamond’s brightness?
- Table percentage
- Crown angle
- Pavilion angle
These factors are crucial for light performance.
What should be emphasized more than a diamond’s numerical parameters?
The way a diamond actually looks
Visual appeal can sometimes outweigh technical specifications.
Define ‘Craftsmanship’ in the context of diamond grading.
The care that goes into the fashioning of a polished diamond
It is confirmed by the diamond’s finish.
What is ‘Culet size’?
The size of the facet at the bottom of the diamond where the pavilion mains meet
This can affect how light exits the diamond.
What does ‘Design’ refer to in diamond grading?
A diamond’s physical shape, including its proportions and durability
It is determined by decisions made during the fashioning process.
What is meant by ‘Finish’ in diamond grading?
The quality of the polish and precision of the cut of a fashioned gemstone
Affects the diamond’s overall appearance.
What is ‘Girdle thickness percentage’?
Girdle thickness expressed as a percentage of average girdle diameter
This measurement helps assess the diamond’s durability.
Define ‘Lower half length percentage’.
The length of the lower half facets expressed as a percentage of the total distance between the girdle and the culet
This is important for evaluating proportions.
What is the ‘Pavilion angle’?
The angle formed by the pavilion mains and the girdle plane
This angle influences how light is refracted within the diamond.
What does ‘Pavilion depth percentage’ indicate?
The distance from the girdle plane to the culet, expressed as a percentage of average girdle diameter
This measurement is critical for assessing a diamond’s cut quality.
