Chapter 7 Flashcards
1
Q
What is the relationship between a diamond and light?
A
It consists of how light strikes the surface, travels within the diamond, and returns to the eye.
2
Q
What are the key elements that affect a polished diamond’s interaction with light?
A
Diamond’s optical properties, design, and quality of its cut.
3
Q
What is reflection in the context of light interaction with surfaces?
A
When part of the light returns to the observer after hitting the boundary of two different materials.
4
Q
What does the law of reflection state?
A
The angle at which light approaches the surface is equal to the angle at which light returns from the surface.
5
Q
What is the angle of incidence?
A
The angle at which a light ray strikes the surface, measured from the normal.
6
Q
What happens to the angle of reflection when the angle of incidence changes?
A
The angle of reflection also changes; they are always equal.
7
Q
What type of surfaces generate high reflection?
A
Smooth surfaces, such as mirrors.
8
Q
What is incident light?
A
Light approaching a surface.
9
Q
What is the difference between high reflection and low reflection?
A
High reflection makes an object look shiny, while low reflection makes it look dull.
10
Q
What occurs during refraction?
A
Part of the light is reflected, while the rest enters the material, changing direction and speed.
11
Q
What is the angle of refraction?
A
The angle between the normal and the refracted light.
12
Q
What is optical density?
A
The ability of a material to slow down light.
13
Q
What is refractive index (RI)?
A
A measure of how the speed and direction of light change in a material compared to in air.
14
Q
What is the refractive index of diamond?
A
2.417.
15
Q
When does refracted light bend toward the normal?
A
When light travels from a less refractive material to a more refractive material.
16
Q
What happens to light when it enters a diamond from the air?
A
It bends toward the normal.
17
Q
Fill in the blank: The angle of incidence is larger than the angle of refraction when light travels from a _______ to a _______ material.
A
less refractive, more refractive
18
Q
True or False: Rough surfaces generate high reflection.
A
False
19
Q
What does the speed of light depend on?
A
The material it travels through
Different materials have varying effects on the speed of light.
20
Q
How do tightly bonded carbon atoms in diamond affect light speed?
A
They dramatically slow incoming light
The structure of diamond’s atoms is crucial in this process.
21
Q
Which materials slow light less than diamond?
A
- Quartz
- Corundum
- Topaz
These materials have atoms that are not as tightly packed and are made of different elements.
22
Q
What is the speed of light in a near-vacuum of outer space?
A
About 300,000 kilometers per second
This is the maximum speed of light in a vacuum.
23
Q
What is the speed of light in water?
A
About 225,000 kilometers per second
Water slows light compared to its speed in a vacuum.
24
Q
What is the speed of light in diamond?
A
About 124,000 kilometers per second
This is significantly slower than in water and a vacuum.
25
What happens to light when it leaves a diamond and returns to air?
It resumes its original speed
## Footnote
This illustrates how light behaves differently in various materials.
26
What happens when light passes from a higher-RI material to a lower-RI material at an angle?
The refracted light bends away from the normal, making the angle of incidence smaller than the angle of refraction.
27
What is total internal reflection?
It occurs when light cannot escape the material anymore and is totally reflected back into the material.
28
What is the critical angle?
The incident angle where the angle of refraction reaches 90 degrees and total internal reflection begins.
29
How does the critical angle vary with the refractive index?
Materials with higher RIs have smaller critical angles, and materials with lower RIs have larger critical angles.
30
Why is the critical angle important to diamond cutters?
It is related to the light performance of fashioned diamonds.
31
What is the critical angle cone?
A cone formed by light rays hitting a surface at the same angle from any direction.
32
What happens to light rays approaching the surface outside the critical angle cone?
They are completely reflected back into the material.
33
What is the ideal path of a light ray entering a diamond?
It enters the crown, strikes the pavilion outside the critical angle, reflects to the opposite side, and then exits.
34
True or False: Light rays can strike a surface at the same angle from only one direction in three-dimensional space.
False
35
What forms a three-dimensional cone around the normal on a facet’s surface?
All light rays that strike a specific point on a facet’s surface.
36
Fill in the blank: Light rays that hit the surface or boundary at the same angle together form a cone called the _______.
critical angle cone
37
What occurs as long as light rays are outside the critical angle cone?
They don’t exit the stone but are reflected internally.
38
What happens to light rays within a polished diamond as they approach the inner surfaces of its facets?
They approach at different points and may exit the diamond almost parallel to the outer surface of the facet.
39
What is the critical angle of diamond?
24.5 degrees.
40
What occurs when the angle of incidence exceeds the critical angle in a diamond?
Total internal reflection occurs.
41
What must light do to achieve total internal reflection in a diamond?
Hit the inner surface of a facet at an angle larger than the critical angle.
42
Why are well-cut diamonds so bright?
Facet angles are designed to reflect as much light internally as possible before it exits the stone.
43
How does the small critical angle of diamond affect light exit opportunities?
It limits the opportunity for light to exit the diamond.
44
What effect does a very deep or very shallow pavilion have on light rays in a diamond?
It forces light rays to approach the inner surfaces at angles smaller than the critical angle, allowing them to exit the stone.
45
True or False: Light rays can exit the diamond if they approach the inner surfaces at angles larger than the critical angle.
False.
46
Fill in the blank: The angle at which light can no longer exit the diamond is called the _______.
[critical angle].
47
What principle affects all aspects of the diamond industry?
The principles of total internal reflection and critical angle
## Footnote
These principles are crucial in understanding how light interacts with diamonds.
48
What remarkable affinity does diamond have?
Diamond has a remarkable affinity for grease and oily substances
## Footnote
This property is utilized in the mining process.
49
How do miners separate diamonds from waste materials?
Miners use a grease table to separate diamonds from waste materials
## Footnote
This method takes advantage of the diamond's affinity for grease.
50
What problem arises when diamonds are mounted in jewelry?
The diamond's surface can become covered with a layer of grease
## Footnote
This affects the optical properties of the diamond.
51
What is the refractive index (RI) of air?
The RI of air is roughly 1
## Footnote
This is a standard value used in optics.
52
What is the refractive index (RI) of grease?
The RI of grease is about 1.5
## Footnote
Grease has a higher RI than air but lower than diamond.
53
What is the critical angle of diamond relative to air?
The critical angle of diamond relative to air is 24.5 degrees
## Footnote
This angle is important for understanding light behavior at the diamond's surface.
54
What is the critical angle of diamond relative to grease?
The critical angle of diamond relative to grease is about 38 degrees
## Footnote
This larger angle can lead to increased light loss.
55
Fill in the blank: Due to the smaller difference in RI between diamond and grease, diamond’s critical angle relative to grease is about _______.
38 degrees
## Footnote
This is compared to the critical angle relative to air.
56
What effect does the larger critical angle relative to grease have on diamonds?
It gives light more opportunity to exit the diamond and cause unnecessary light loss
## Footnote
This can make the diamond appear dull.
57
What is white light?
A combination of spectral colors, each with a different wavelength and energy.
58
Do the colored wavelengths of white light travel at the same speed in a vacuum?
Yes, they travel at the same speed in a vacuum.
59
What happens to the speed of white light in different mediums?
It travels at different speeds in any other medium or material.
60
What is dispersion?
An optical phenomenon where white light separates into its spectral colors.
61
What causes dispersion?
The difference in the speed of colored wavelengths when entering a material with a high refractive index (RI).
62
In a diamond, which color of light slows down more?
Violet light.
63
Which color of light bends more in a diamond?
Violet light bends more than red light.
64
What is the refractive index (RI) of violet light in a diamond?
2.451.
65
What is the refractive index (RI) of red light in a diamond?
2.407.
66
What is the measure of diamond's dispersion?
0.044, the difference between the RI of violet and red light.
67
How is a material’s dispersion measured?
By the RI difference between the violet and red light rays in the material.
68
What characteristic property helps distinguish diamonds from other transparent gems?
Dispersion.
69
Fill in the blank: Dispersion is an optical property that is characteristic for a _______.
[material].
70
What is the total distance that a light ray travels in a gemstone called?
Path length
## Footnote
Path length influences color appearance due to visible light absorption.
71
How does path length affect color appearance in gemstones?
Greater distance light travels leads to more absorption
## Footnote
Thicker portions of a material absorb more light.
72
What can modify the path length in gemstones?
Cutting
## Footnote
Careful and skilled cutting can optimize path length.
73
What is the effect of well-cut diamonds compared to poorly cut stones?
Better light performance and color appearance
## Footnote
Well-cut diamonds are typically more attractive.
74
What attributes demonstrate a diamond's light performance?
Brightness, fire, and scintillation
## Footnote
These attributes are affected by the quality of the diamond's cut.
75
How do cutters typically design diamonds for brightness?
By ensuring light rays reflect outside the critical angle
## Footnote
This design allows light to reflect back toward the crown.
76
What does brightness in diamonds refer to?
The amount of light that returns to the observer's eye
## Footnote
It can be reflected off the inside of the diamond or crown facets.
77
Fill in the blank: The design of the cut affects the appearance of _______ in colored diamonds.
Color
## Footnote
The cut design plays a critical role in how color is perceived.
78
True or False: A skillfully cut diamond's proportions do not influence its interaction with light.
False
## Footnote
Well-cut diamonds optimize their interaction with light.
79
What is the primary factor contributing to a diamond's brightness?
Extremely high luster
## Footnote
Luster is the appearance of the surface in reflected light.
80
How does the refractive index (RI) of a material relate to its luster?
Materials with higher RIs tend to have higher luster.
81
What surface condition produces a clear reflection in gemstones?
A smooth, even surface.
82
What effect do uneven surfaces have on light reflection?
They appear fuzzy or frosty.
83
What is the refractive index of diamond described as?
Exceptionally high.
84
What characteristic of diamonds allows them to maintain a superior polish?
Superior hardness.
85
What term describes the distinctive luster of a finished diamond?
Adamantine.
86
What does the term 'adamantine' mean?
Diamond-like.
87
What is the highest luster description for transparent gemstones?
Adamantine.
88
What type of luster do most other gems have?
Vitreous luster.
89
What does vitreous luster mean?
Glass-like.
90
When light strikes a well-polished diamond at a 90-degree angle, what percentage is reflected?
17 percent.
91
What percentage of light enters a well-polished diamond when struck at a 90-degree angle?
83 percent.
92
How much light does glass reflect when struck at a 90-degree angle?
4 percent.
93
What can distinguish diamonds from most other gemstones?
Adamantine luster.
94
What factors influence the brightness and darkness of a diamond?
Reflection of the observer and their clothing color.
95
Fill in the blank: The gem reflects the ________, which affects the brightness of the diamond.
observer.
96
What are the two components of scintillation?
Sparkle and pattern
## Footnote
Sparkle appears as flashing spots of light, while pattern involves the arrangement and contrast of bright and dark areas.
97
What does sparkle in a diamond refer to?
Flashing spots of light
## Footnote
In a well-cut diamond, sparkle is evenly distributed and balanced in size.
98
What factors contribute to the pattern in a diamond's scintillation?
Relative size, arrangement, and contrast of bright and dark areas
## Footnote
Bright areas result from surface and internal reflections, while dark areas may represent loss of light or reflections from surrounding objects.
99
What effect does a steep crown or deep pavilion have on a diamond's appearance?
Makes the diamond darker
## Footnote
Standard dimensions for crown or pavilion would typically allow more light, making the diamond appear brighter.
100
What happens if a diamond has an off-center culet?
The diamond’s pattern becomes off-center
## Footnote
This misalignment affects the overall appearance of the diamond.
101
How does contrast between bright and dark areas affect a diamond's appearance?
Gives the pattern a crisp, sharp look
## Footnote
A lack of contrast can make a diamond appear dull and gray.
102
What is the effect of prominent dark areas in a diamond?
Detracts from the diamond’s face-up appearance
## Footnote
Excessively dark patterns can result from the cutter's choices to retain weight from the rough.
103
What is the fish-eye pattern in a diamond?
A pale gray reflection of the girdle just inside the table facet
## Footnote
This pattern is typically caused by a shallow pavilion.
104
What does the term 'nailheads' refer to in diamond patterns?
Dark area in the center of the table facet
## Footnote
This pattern can affect the diamond's overall aesthetic.
105
What characterizes the dark radiating mains pattern in diamonds?
A dark spoke-like pattern of radiating pavilion mains
## Footnote
This pattern can contribute to a diamond's perceived darkness.
106
Fill in the blank: A diamond pattern that lacks contrast can look _______.
Dull and gray
## Footnote
Contrast is essential for a diamond's brilliance.
107
True or False: Light leakage from a diamond can enhance its optical performance.
False
## Footnote
Light leakage typically diminishes a diamond's optical performance.
108
What is the hearts and arrows pattern?
A highly desired diamond cut that shows heart and arrow shapes
## Footnote
This pattern is familiar among consumers and is often patented and branded.
109
How does a polished diamond interact with light?
The interaction is complex
## Footnote
Not all diamonds with high brightness and fire have attractive patterns.
110
What impact do patterns have on a diamond's appearance?
Some patterns can detract from a diamond's appearance more than others
## Footnote
Examples include fish-eyes and dark centers.
111
What are fish-eyes in diamonds?
A detrimental pattern that negatively affects a diamond's appearance
## Footnote
Fish-eyes are often considered undesirable.
112
What effect do dark centers have on a diamond?
They are very detrimental to a diamond’s appearance
## Footnote
Dark centers can make the diamond look less appealing.
113
When are dark radiating mains distracting in a diamond?
When they extend beyond the table facet, cause the center around the culet to appear dark face-up, or both
## Footnote
This can significantly affect the visual appeal of the diamond.
114
What term describes a diamond’s display of dispersion?
Fire
115
What does 'fire' refer to in the context of diamonds?
The rainbow colors visible when you move a well-cut diamond under an overhead spotlight
116
What causes fire in a diamond?
The arrangement of a diamond’s facets and the angles between them
117
True or False: Every diamond shows the same amount of fire.
False
118
What influences the fire seen in the face-up view of a diamond?
Four factors
1.The angle at which light enters the diamond
2. The number of times the light ray interacts with the diamond’s internal facets
3. Facet junctions
4. The angle at which the light rays exit the diamond
119
Fill in the blank: Not all gems separate light enough for dispersion to be visible, but _______ do.
diamonds
120
Do all diamonds have the same dispersion value?
Yes
121
What effect does the angle of incidence have on light?
It affects the way light separates into its spectral colors.
122
What happens when a light ray strikes perpendicular to a facet surface?
It travels into the gem without separating.
123
What occurs at greater angles of incidence?
The spread of spectral colors widens.
124
True or False: A light ray strikes a facet surface at a perpendicular angle; it will separate into spectral colors.
False
125
Fill in the blank: At greater angles, the spread of spectral colors _______.
widens
126
What happens when a ray of white light enters a diamond?
It begins to separate into its spectral colors.
## Footnote
This process is known as dispersion.
127
What effect does the angle of incidence have on the dispersion of light in a diamond?
The greater the angle, the greater the refraction.
## Footnote
At a maximum interior angle of incidence of 24.5 degrees, the spread of colors is more visible.
128
At what angle of incidence is the difference between the angles of refraction for violet and red light very small?
One degree.
## Footnote
At one degree, the difference is less than one one-hundredth of a degree.
129
How does the number of interactions a light ray has with a diamond's internal facets affect dispersion?
Dispersion increases every time light reflects or refracts.
## Footnote
This occurs many times in a well-cut diamond.
130
What is the relationship between path length in a diamond and the visibility of spectral colors?
The longer the path length, the greater the difference between spectral colors, making them more visible.
131
What role do facet junctions play in the dispersion of light within a diamond?
They influence the paths of colored light rays, allowing them to take different routes and contribute to fire.
132
How does the exit angle of light rays affect the fire of a diamond?
The smaller the exit angle, the larger the angle of refraction, spreading the colored bands farther apart.
133
What design feature in diamond cuts can enhance fire?
Higher numbers of crown facets.
## Footnote
This design takes advantage of light dispersion.
134
How does diffused lighting affect a diamond's appearance?
It emphasizes brightness but suppresses fire.
## Footnote
Diffused lighting comes from all angles, impacting how light interacts with the diamond.
135
Fill in the blank: The first factor affecting fire in a diamond is the angle at which light _______.
enters the diamond.
136
True or False: The angle of light entry does not affect the fire of a diamond.
False.
137
What is directional lighting also called?
Spot lighting or point source lighting
138
What effect does directional lighting have on a diamond?
It strikes a diamond only from certain angles, contrasting with surrounding dark areas to bring out the fire in a diamond
139
What types of lighting create a balance between brightness and fire in diamonds?
A mix of fluorescent and incandescent lighting
140
How can one best observe the fire in a diamond?
By rocking and tilting it and changing its orientation
141
What must occur for the dispersed light waves to be seen as fire?
They must travel separately to your eye
142
What happens to colored light as it exits a diamond?
It can recombine into white light
143
Why are diamonds best appreciated face-up?
Cutters direct the greatest display of fire through the gem’s crown
144
What can produce the appearance of fire in a diamond?
Background colors, like clothing or objects of contrasting color surrounding a diamond
145
How is a diamond's color appearance related to visible light?
It is directly related to its absorption of visible light
146
What influences the color appearance of a diamond?
Where and how much absorption occurs on the visible spectrum
147
What dictates where absorption occurs in a diamond?
The types of defects
148
What determines the amount of absorption in a diamond?
The concentrations of the defects and light path length
149
What factors determine the types of defects in a diamond?
Nature during diamond formation
150
What is the only factor humans can control regarding diamond absorption?
The path length that light travels in a diamond
151
What can cutters do to change the path length in a diamond?
Cut and recut the diamond
152
Why is controlling the path length important for colored diamonds?
It affects the color appearance of a faceted stone
153
What does the path length of a light ray within a diamond depend on?
The arrangement of the facets and the angles between them.
## Footnote
The specific geometry affects how light travels through the diamond.
154
How can cutters affect the path length of light in a diamond?
By changing the cutting style.
## Footnote
Different cutting styles can manipulate the angles and arrangement of facets.
155
Fill in the blank: The path length of a light ray within a diamond can be _______ by changing the cutting style.
elongated or shortened.
156
What happens to light when it enters a diamond?
It keeps traveling within the stone until it exits.
157
What determines the total distance light travels before exiting a diamond?
The angles and arrangement of the stone’s facets.
158
How can cutters influence the path that light travels in a diamond?
Through cut design.
159
What is the effect of a shortened path length in a diamond?
Less absorption, resulting in a lighter color.
160
What happens when the path length in a diamond is longer?
Increased absorption, giving the diamond a deeper color.
161
Why is optimization of color appearance important for cutters?
It is a critical skill for cutters dealing with colored diamonds.
162
Fill in the blank: A _______ path length results in less absorption in a diamond.
shortened
163
True or False: The cut design of a diamond has no effect on the light path.
False
164
What contributes to a diamond's overall cut grade?
Each facet in a well-cut diamond
165
What do the facets of a diamond interact with?
Light
166
What affects a diamond's face-up appearance?
The interaction of facets with light
167
What two factors contribute to a diamond's appearance?
Basic proportions and precision of facets
168
How does every angle and facet affect a diamond?
Affects the amount of light returned or lost
169
What is often considered the most important value factor in a purchasing decision for diamonds?
Cut
170
What are proportions in the context of a diamond?
The angles and relative measurements of a polished gem
171
What role do proportions play in a diamond?
Key role in light performance and appearance
172
What is the most critical decision for a diamond cutter?
The proportions of a finished diamond
173
For a reliable cut grading system, what must be answered?
Two important questions regarding proportions and appearance
174
What are the two important questions that must be answered for a cut grading system?
* What changes in proportions create distinctions in appearance visible to an observer?
* Which proportions are attractive or unattractive to most observers?
175
What organization conducted research on diamond cut?
GIA
## Footnote
GIA stands for Gemological Institute of America.
176
What technology did GIA develop to study diamond light behavior?
An advanced light ray tracing computer program
177
What was the purpose of GIA's diamond cut research?
To understand how light behaves within a round brilliant diamond
178
How many observations were made during GIA's testing?
More than 70,000
179
What aspects of diamonds were assessed in GIA's observations?
* Brightness
* Fire
* Cut appearance
180
What did GIA's research determine about diamond proportions?
A range of proportions can enhance a diamond's beauty
181
What system was developed as a result of GIA's research and testing?
The GIA Diamond Cut Grading System
182
True or False: The GIA Diamond Cut Grading System allows only a single set of proportions.
False
183
Fill in the blank: The majority of people prefer diamonds in the _______ cut grades.
top
184
What types of observers participated in GIA's testing?
Observers from all sectors of the industry, including consumers
185
What was the purpose of GIA's largest-scale observation testing?
To validate the results of light ray tracing research on diamond proportions
## Footnote
The testing aimed to ensure the accuracy of the grading system based on actual observations.
186
How many round brilliant diamonds were tested in GIA's observation study?
More than 2,300 round brilliant diamonds
## Footnote
The diamonds included various proportion combinations.
187
Who were the observers selected for the diamond testing?
Observers included industry professionals and consumers
## Footnote
This diverse selection contributed to the reliability of the results.
188
What was one of the key outcomes of the testing regarding brightness and fire?
Validated the computer modeling for brightness and fire
## Footnote
This refinement ensured results reflected actual diamond appearances under standard lighting.
189
What other components of face-up appearance were analyzed during the testing?
Scintillation and aspects of cut quality
## Footnote
Design and craftsmanship were also included in the analysis.
190
What did the researchers determine about observer variation in diamond components?
Determined how much variation in any component observers could consistently see
## Footnote
This included levels of brightness and the number of distinguishable cut grade categories.
191
What inherent aspect did researchers discover about grading systems?
Personal and regional preferences in appearance
## Footnote
This suggests multiple equally attractive appearances can exist within a grade category.
192
What predictive system did GIA create as a result of the observation testing?
A predictive diamond cut grading system
## Footnote
This system predicts cut grades consistent with those assigned by the majority of observers.
193
How many proportion combinations are in the cut database created by GIA?
More than 38.5 million proportion combinations
## Footnote
The database supports diamond manufacturers in their cutting decisions.
194
True or False: The predictive nature of GIA's system allows for consistent cut grade predictions.
True
## Footnote
The predictions are aligned with the majority of observer assessments.
195
What grading system is applied to round brilliant diamonds?
GIA Cut Grading System
196
What are the five cut grades assigned by the GIA Cut Grading System?
* Excellent (Ex)
* Very Good (VG)
* Good (G)
* Fair (F)
* Poor (P)
197
What additional factors should be considered when grading a round brilliant diamond?
* Design quality
* Craftsmanship
198
What does 'design' refer to in the context of diamond grading?
A fashioned diamond’s proportions and durability
199
What is craftsmanship in diamond grading?
Evidenced by the gem’s polish and symmetry
200
What is 'polish' in the context of diamonds?
The overall condition of the facet surfaces of a finished diamond
201
What does 'symmetry' describe in diamond grading?
The exactness of a finished gem’s shape and the placement of its facets
202
What qualities make a diamond attractive?
* Bright
* Fiery
* Sparkling
* Pleasing overall appearance
203
What cut grade virtually guarantees an attractive diamond?
Excellent (Ex)
204
Are diamonds graded Very Good and Good also considered beautiful?
Yes
205
How have advancements in cutting technology affected the availability of diamonds graded Fair and Poor?
Diamonds graded Fair and Poor are not as common
206
What are the three main aspects used to estimate a diamond's cut grade?
Brightness, pattern, fire
## Footnote
These aspects are visually evaluated to determine the quality of a diamond's cut.
207
Why is a standardized viewing environment important for diamond grading?
It ensures consistent and repeatable results
## Footnote
Variations in lighting and background can affect the perceived quality of a diamond.
208
What type of lighting is beneficial for evaluating a diamond's brightness and pattern?
Diffused fluorescent lighting
## Footnote
This type of lighting helps to assess these characteristics but may suppress fire.
209
What effect does spot lighting have on a diamond's appearance?
It emphasizes fire but can overwhelm other characteristics
## Footnote
If the spot lighting is too strong, it may make the gem appear dark.
210
What is the GIA DiamondDockTM designed to provide?
Consistent and repeatable viewing conditions
## Footnote
This tool helps in standardizing the grading process for diamonds.
211
What type of light does the GIA DiamondDockTM use for judging brightness?
Daylight-equivalent diffused fluorescent light
## Footnote
This lighting is crucial for assessing brightness and face-up pattern.
212
What type of lights does the GIA DiamondDockTM use to judge fire?
An array of light-emitting diodes (LEDs)
## Footnote
LEDs are effective for evaluating the fire characteristic of diamonds.
213
Fill in the blank: Diamonds reflect everything around them, including a viewer's or grader's _______.
clothing
## Footnote
This reflection can influence the grading results.
214
True or False: The same diamond looks the same under all types of lighting.
False
## Footnote
Diamonds can appear quite different depending on the lighting conditions.
215
What is the first step a grader takes after cleaning a diamond?
The grader puts the diamond face-up in a grading tray
## Footnote
The tray is then placed into the lighting environment.
216
What type of light does the grader first use to assess the diamond’s brightness?
Fluorescent light
## Footnote
This light helps evaluate the diamond's brightness and pattern.
217
How is the diamond’s brightness rated?
From Excellent to Poor
## Footnote
The rating depends on how 'lively' the stone appears.
218
What does the grader assess after brightness to assign a pattern grade?
The amount of contrast and the balance between bright and dark areas
## Footnote
This also receives a rating from Excellent to Poor.
219
What lighting is used to evaluate the diamond’s fire?
Spot lighting
## Footnote
This helps assess the flashes of fire visible in the diamond.
220
What is the rating scale for the diamond’s fire?
From Excellent to Poor
## Footnote
This rating reflects the visible flashes of fire.
221
How is the initial cut grade estimate determined?
Based on the lowest rating assigned for brightness, fire, or pattern
## Footnote
For example, if brightness and fire are Very Good but pattern is Good, the cut grade estimate is Good.
222
What is assessed after the visual assessment of face-up appearance?
The diamond’s proportions
## Footnote
This is part of the grading process.
223
What additional factors are considered for the overall cut grade?
Symmetry and polish
## Footnote
These factors complete the overall assessment of the diamond's cut quality.
224
What are the three cut quality factors?
* Face-Up appearance
* Design
* Craftsmanship
## Footnote
These factors contribute to the overall quality of the diamond's cut.
225
True or False: A penlight or small flashlight can be used to assess a diamond's fire.
True
## Footnote
This is an optional method for grading.
226
What type of light is also acceptable for grading brightness and pattern?
A microscope’s overhead fluorescent light
## Footnote
This provides another method to evaluate these aspects.
