|
| |
|
|
When choosing a diamond there are 4 qualities to keep in mind.
Cut | Color | Clarity | Carat Weight
|
|
| The cut of a diamond - its roundness, its depth and width, the uniformity of the facets - all determine a diamond's ability to reflect brilliance. Many gemologists consider the cut the most important diamond characteristic because even if a diamond has perfect color and clarity, a diamond with a poor cut will have dulled brilliance.
The width and depth have the greatest affect on how light travels within the diamond, and how it exits in the form of brilliance.
|
Too Shallow: Light is lost out the sides causing the diamond to lose brilliance.
Too Deep: Light escapes out the bottom causing the diamond to appear dark and dull. |
The diamonds proportions, specifically the depth compared to the diameter, and the diameter of the table compared to the diameter of the diamond, determine how well light will reflect and refract within the diamond.
|
|
Diameter: The width of the diamond as measured through the girdle. |
Table: The largest facet of a gemstone. |
Crown: The top portion of a diamond extending from the girdle to the table. |
Girdle: The narrow band around the widest part of a diamond. |
Pavilion: The bottom portion of a diamond, extending from the girdle to the culet. |
Culet: The facet at the tip of a gemstone. The preferred culet is not visible with the unaided eye (graded "medium" or "none"). |
Depth: The height of a gemstone measured from the culet to the table. |
|
These proportions are calculated and applied to a cut grading scale that makes it easy to understand how well each reflect light:
- Ideal cut: Represents roughly the top 3% of diamond quality. Reflects nearly all light that enters the diamond. An exquisite and rare cut.
|
- Very good cut: Represents roughly the top 15% of diamond quality. Reflects nearly as much light as the ideal cut, but for a lower price.
|
- Good cut: Represents roughly the top 25% of diamond quality. Reflects most light that enters. Much less expensive than a very good cut.
|
- Fair cut: Represents roughly the top 35% of diamond quality. Still a quality diamond, but a fair cut will not be as brilliant as a good cut.
|
- Poor cut: This includes all diamonds that do not meet the proportion standards of a fair cut. These diamonds are deep and narrow or shallow and wide and tend to lose most of the light out the sides and bottom.
|
Which Cut Grade is Best
- For a diamond with the best cut, even when viewed a microscope, look for cut grades of ideal or very good, and polish and symmetry grades of ideal or excellent.
|
- For a diamond that has no visible difference when compared with the naked eye to more expensive cuts, choose a diamond with a cut grade of good, and polish and symmetry grades of very good or good.
|
- For excellent value with an ideal- or very-good cut diamond with very good or good polish and symmetry, consider less expensive grades of color and clarity — look for a diamond with G or H color and SI1 or SI2 clarity.
|
*Article courtesy of Blue Nile
top of page
|
|
| The color of a diamond has the second biggest impact on its price, after carat weight. Did you know that diamonds come in every color of a rainbow?
Grading color in the normal range involves deciding how closely a stone's body color approaches colorlessness. Most diamonds have at least a trace of yellow or brown body color. With the exception of some natural fancy colors, such as blue, pink, purple, or red, the colorless grade is the most valuable.
If a diamond does not have enough color to be called fancy, then it is graded in a scale of colors ranging from Colorless to Light Yellow, "D" through "Z". A diamond with a "D" color is considered to be colorless. If the color is more intense than "Z", it is considered fancy. A fancy yellow diamond fetches a higher price than a light yellow diamond.
The Laboratories only grade diamonds which are unmounted, or "loose", and they do so under special light. Once a loose diamond is mounted on a ring, even the trained professional cannot always tell the difference between, say a "D" color and an "E" or "F" color diamond!
| Color |
D |
E |
F |
G |
H |
I |
J |
K |
L |
M |
N |
O |
P |
Q |
R |
S |
T |
U |
V |
W |
X |
Y |
Z |
Fancy |
| Scale |
Colorless |
Near Colorless |
Faint Yellow |
Very Light Yellow |
<------Light Yellow------> |
Color |
*Article courtesy of diamondgrading.com
top of page
|
|
|
| The clarity of a diamond refers to how clear, or "clean" the diamond is. The more "clean" the diamond, the higher the price. Most diamonds have "imperfections" in them. The clarity scale is a measure of the severity of those imperfections or "inclusions" as it is known in the trade.
For example, a deep break in a diamond which is not that visible when you look at the stone face-up, could sometimes have a greater impact on the clarity of a stone, than a small black crystal which you can see very clearly face-up.
The following is the Diamond clarity-scale:
FL-Flawless
These stones have no imperfections inside or on the outside of the stone under the magnification of a loupe of 10 power.
IF-Internally Flawless
These stones have no inclusions under a loupe with a 10 power magnification.
VVS1,VVS2-Very Very Slightly Imperfect
These stones have very small inclusions which are very difficult to see under a loupe with a 10 power magnification.
VS1,VS2-Very Slightly Imperfect
These stones have small inclusions which are slightly difficult to difficult to see under a loupe with a 10 power magnification.
SI1,SI2-Slightly Imperfect
These stones have inclusions which are fairly easy to see under a loupe with a 10 power magnification, or visible to the naked eye.
I1,I2,I3-Imperfect
These stones have inclusions which range from eye visible to very easily seen to the naked eye.
| Clarity |
FL |
IF |
VVS1 |
VVS2 |
VS1 |
VS2 |
SI1 |
SI2 |
I1 |
I2 |
I3 |
Scale |
Flawless-
Internally Flawless |
Very Very Slightly Imperfect |
Very Slightly Imperfect |
Slightly Imperfect |
Imperfect |
SI3
Outside of the GIA Diamond clarity scale is a grade you may have seen called SI3. The Rap Sheet, which is a Trade Publication, honors the SI3 grade which is given out by EGL, the European Gemological Laboratory. It is described as a split between the SI2 and I1 clarity grade.
*Article courtesy of diamondgrading.com
top of page
|
|
| The size of a diamond has the biggest impact on its price. The metric carat, which equals 0.20 gram, is the standard unit of weight for diamonds and most other gems. If other factors are equal, the more a stone weighs, the more valuable it will be.
Here are several ways to express 1 carat:
1 ct.
200 milligrams
1/5 gram
100 points
4 grainer (not often used in retail environment)
It is very important not to mistake carat weight as referring to the dimensions of a diamond. It refers to weight only. Why the distinction? Because weight can hide in different parts of the stone. You can have a) well-cut, b) deep, or c) shallow Diamonds. Some may appear larger than others due to its cut.
How "big" is a carat?
Many people would like to "understand" carat sizes in real terms. Here's a simple trick to get an idea. Simply take a ruler, and look at the table below. These are some approximate, sample carat-weight to diameter-widths for popular sizes.
0.25 ct. - 4.1 mm  |
0.50 ct. - 5.2 mm  |
0.75 ct. - 5.9 mm  |
1.00 ct. - 6.5 mm  |
*Article courtesy of diamondgrading.com
top of page
|
|
