Diamonds and Light (Chapter 8, Key Terms & Key Concepts) Flashcards
The highest degree of luster
possible in a transparent material.
Adamantine luster
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
The effect of all the diamond’s internal
and external reflections of white light.
Brightness
Angle 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 flashes of color you see in a polished
diamond
Fire
The appearance of a material’s surface in
reflected light.
Luster
An imaginary line perpendicular to the point
where a ray of light strikes the surface.
Normal
The relative size, arrangement, and contrast
of bright and dark areas that result from a diamond’s
internal and external reflections.
Pattern
The overall condition of the facet surfaces of
a finished diamond.
Polish
The angles and relative measurements
of a polished gem and the relationships between
them
Proportions
The bouncing back of light when it
strikes a surface.
Reflection
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 angle of light as it passes from one
material to another.
Refractive index (RI)
The flashes of light and the contrasting
dark areas you see when the diamond, the light, or
the observer moves.
Scintillation
The exactness of a finished gem’s shape
and the placement of its facets
Symmetry
The passage of light into or through a
material.
Transmission
The distance between two adjacent
high points of an energy wave.
Wavelength
A fashioned diamond’s optical display is meant to be seen
face-up and in motion
Key concept
A skilled cutter’s faceting and proportion choices unlock a
diamond’s unique optical potential
Key Concept
Light is a form of radiant energy that travels in waves.
Key Concept
Visible light is a small portion of the electromagnetic
spectrum.
Key Concept
White light is a combination of all the spectral colors.
Key Concept
The angle of incidence always equals the angle of reflection.
Key Concept
A material’s optical density affects the speed of the light
that passes through it.
Key Concept
Light rays that enter at the maximum angle of refraction
form a critical angle cone inside the diamond.
Key Concept
The higher a gem’s RI, the smaller its critical angle
Key Concept
White light breaks up into its component colors when it
passes at an angle into a denser material.
Key Concept
Each spectral color has its own RI and angle of refraction.
Key Concept
All diamonds have the same dispersion value, but differences
in diamond cut bring out differing amounts of fire.
Key Concept
A diamond’s face-up pattern reveals almost all of the cutter’s
fashioning choices.
Key Concept
GIA diamond cut grades apply to standard round brilliants in
all clarities across the D-to-Z color range.
Key Concept
Variations in lighting and surroundings can affect a diamond’s
appearance.
Key Concept
Diffused fluorescent lighting helps you evaluate a diamond’s
brightness and pattern, while spotlighting helps you evaluate
its fire.
Key Concept
Variations in lighting and surroundings can affect a diamond’s
appearance
The higher the optical density of a material, the
more it slows light down.
The combined effect of all the diamond’s surface and internal white light reflections is its
brightness.
Grease on the pavilion of a diamond results in
more light leakage through the pavilion.
The angle of incidence always equals the
angle of reflection.
White light is actually
a combination of all the spectral colors.
The change in speed and possible change in direction of light as it travels from one material to another is called
retest
The change in speed and possible change in direction of light as it travels from one material to another is called
refraction.
The appearance of a material’s surface in reflected light is called
luster.
The relative size, arrangement, and contrast of bright and dark areas that result from a diamond’s internal and external reflections is called
pattern.
The difference between the RI values of specific violet and red wavelengths of visible light for a given material is its
dispersion.
In order to exit a diamond, light must strike an inner surface
inside the critical angle.
The flashes of light and the contrasting dark areas you see when the diamond, the light, or the observer moves are called
scintillation.
Visible light is
a form of radiant energy.
The passage of light into or through a material is called
transmission.
The flashes of color you see in a polished diamond are called
fire.
