Diamonds and Light (Chapter 8, Key Terms & Key Concepts)

Question 1

The highest degree of luster
possible in a transparent material.

Answer 1

Adamantine luster

Question 2

The angle at which a ray of light
strikes a surface, measured from the normal.

Answer 2

Angle of incidence

Question 3

The angle between the normal
and a reflected ray of light.

Answer 3

Angle of reflection

Question 4

The effect of all the diamond’s internal
and external reflections of white light.

Answer 4

Brightness

Question 5

Angle between the normal and the
maximum angle of refraction, which is the largest
angle at which rays inside the diamond can escape

Answer 5

Critical angle

Question 6

An optical property that’s the difference
between the RI values of specific violet and red
wavelengths of visible light for a given material.

Answer 6

Dispersion

Question 7

The flashes of color you see in a polished
diamond

Answer 7

Fire

Question 8

The appearance of a material’s surface in
reflected light.

Answer 8

Luster

Question 9

An imaginary line perpendicular to the point
where a ray of light strikes the surface.

Answer 9

Normal

Question 10

The relative size, arrangement, and contrast
of bright and dark areas that result from a diamond’s
internal and external reflections.

Answer 10

Pattern

Question 11

The overall condition of the facet surfaces of
a finished diamond.

Answer 11

Polish

Question 12

The angles and relative measurements
of a polished gem and the relationships between
them

Answer 12

Proportions

Question 13

The bouncing back of light when it
strikes a surface.

Answer 13

Reflection

Question 14

Change in speed and possible change in
direction of light as it travels from one material to
another.

Answer 14

Refraction

Question 15

A measure of the change in
the speed and angle of light as it passes from one
material to another.

Answer 15

Refractive index (RI)

Question 16

The flashes of light and the contrasting
dark areas you see when the diamond, the light, or
the observer moves.

Answer 16

Scintillation

Question 17

The exactness of a finished gem’s shape
and the placement of its facets

Answer 17

Symmetry

Question 18

The passage of light into or through a
material.

Answer 18

Transmission

Question 19

The distance between two adjacent
high points of an energy wave.

Answer 19

Wavelength

Question 20

A fashioned diamond’s optical display is meant to be seen
face-up and in motion

Answer 20

Key concept

Question 21

A skilled cutter’s faceting and proportion choices unlock a
diamond’s unique optical potential

Answer 21

Key Concept

Question 22

Light is a form of radiant energy that travels in waves.

Answer 22

Key Concept

Question 23

Visible light is a small portion of the electromagnetic
spectrum.

Answer 23

Key Concept

Question 24

White light is a combination of all the spectral colors.

Answer 24

Key Concept

Question 25

The angle of incidence always equals the angle of reflection.

Answer 25

Key Concept

Question 26

A material’s optical density affects the speed of the light that passes through it.

Answer 26

Key Concept

Question 27

Light rays that enter at the maximum angle of refraction form a critical angle cone inside the diamond.

Answer 27

Key Concept

Question 28

The higher a gem’s RI, the smaller its critical angle

Answer 28

Key Concept

Question 29

White light breaks up into its component colors when it passes at an angle into a denser material.

Answer 29

Key Concept

Question 30

Each spectral color has its own RI and angle of refraction.

Answer 30

Key Concept

Question 31

All diamonds have the same dispersion value, but differences in diamond cut bring out differing amounts of fire.

Answer 31

Key Concept

Question 32

A diamond’s face-up pattern reveals almost all of the cutter’s fashioning choices.

Answer 32

Key Concept

Question 33

GIA diamond cut grades apply to standard round brilliants in all clarities across the D-to-Z color range.

Answer 33

Key Concept

Question 34

Variations in lighting and surroundings can affect a diamond’s appearance.

Answer 34

Key Concept

Question 35

Diffused fluorescent lighting helps you evaluate a diamond's brightness and pattern, while spotlighting helps you evaluate its fire.

Answer 35

Key Concept

Question 36

Variations in lighting and surroundings can affect a diamond’s

Answer 36

appearance

Question 37

The higher the optical density of a material, the

Answer 37

more it slows light down.

Question 38

The combined effect of all the diamond’s surface and internal white light reflections is its

Answer 38

brightness.

Question 39

Grease on the pavilion of a diamond results in

Answer 39

more light leakage through the pavilion.

Question 40

The angle of incidence always equals the

Answer 40

angle of reflection.

Question 41

White light is actually

Answer 41

a combination of all the spectral colors.

Question 42

The change in speed and possible change in direction of light as it travels from one material to another is called

Answer 42

retest

Question 43

The change in speed and possible change in direction of light as it travels from one material to another is called

Answer 43

refraction.

Question 44

The appearance of a material’s surface in reflected light is called

Answer 44

luster.

Question 45

The relative size, arrangement, and contrast of bright and dark areas that result from a diamond’s internal and external reflections is called

Answer 45

pattern.

Question 46

The difference between the RI values of specific violet and red wavelengths of visible light for a given material is its

Answer 46

dispersion.

Question 47

In order to exit a diamond, light must strike an inner surface

Answer 47

inside the critical angle.

Question 48

The flashes of light and the contrasting dark areas you see when the diamond, the light, or the observer moves are called

Answer 48

scintillation.

Question 49

Visible light is

Answer 49

a form of radiant energy.

Question 50

The passage of light into or through a material is called

Answer 50

transmission.

Question 51

The flashes of color you see in a polished diamond are called

Answer 51

fire.