Assignment 7 - The path light travels Flashcards
The effect of all diamond’s internal and external reflections of white light
Brightness
The flashes of color you see in a polished diamond
Fire
The flashes of light and the contrasting dark areas you see when the diamond, the light or the observer moves
Scentillation
The angles and relative measurements of a polished gem and the relationship between them
Proportions
The bouncing back of light when it strikes a surface
Reflection
The angle at which a ray of light strikes a surface, measured from the normal
Angle of incidence
The angle between the normal and a reflected ray of light
Angle of reflection
An imaginary line perpendicular to the point where a ray of light strikes the surface
Normal
Change in speed and possible change in direction of light as it travels from one material to another
Refraction
A measure of the change in the speed and the angle of light as it passes from one material to another
Refractive Index (RI)
Angel between the normal and the maximum angle of refraction, which is the largest angle at which rays inside the diamond can escape
Critical angle
An optical property that’s the difference between the RI values of specific violet and red wavelengths of visible light for a given material.
Dispersion
The appearance of a material’s surface in reflected light.
Luster
The highster degree of luster possible in a transparent material
Adamantine Luster
Which proportions contribute the most to a diamond’s brightness?
Pavillion proportions
What factors influence the amount of fire a diamond displays?
- the angle at which light enters a diamond
- number of times a light ray interacts iwth the internal facets
- factet junctions
- angle the light exits
What are the two components of scintillation?
Sparkle (flashing spots of light) and pattern (of light and dark areas)
The relative size, arrangement, and contrast of bright and dark areas that result from a diamond’s internal and external reflections.
Pattern
What are the cut grades in the GIA system?
- Excellent
- Very good
- Good
- Fair
- Poor
Why is proper lightning important to diamond cut grading?
Variations in lightning and surroundings can affect a diamond’s appearance.
What type of lightning is preferable to grade a cut?
- Diffused fluorescent lightning helps to evaluate a diamond’s brightness and pattern.
- Spotlighting helps you evaluate its fire.
The exactness of a finished gem’s shape and the placement of its facet
Symmetry
The overall condition of the facet surfaces of a finished gem.
Polish
What are diamond’s light performance attributes?
- Brightness
- Fire
- Scintillation
What’s the critical angle of a diamond?
24.5 degrees
Which pattern is caused by a shallow pavilion?
Fish-Eye
Which pattern is caused by a deep pavilion?
Nailhead (Dark pattern)
