QUICK JUMP LINKS : Diamond Grading | The 4 C's | Cut | Color | Clarity | Carat | Diamond Shapes | Appraisals vs Certificates | What is a Diamond | Moh's Hardness Scale
| DIAMOND GRADING - THE 4 C's |
| Diamond grading, which includes the evaluation of different attributes known commonly as "the four Cs", is a set of criteria by which the value and quality of diamonds are measured.
|
| THE 4 C'S - CUT |
Cut is the most important of these factors, as proper cutting of a diamond is essential in bringing out the sparkle and fire that made this gem famous. A poorly planned or executed cutting technique can permanently ruin a top-quality diamond, and conversely a lower quality diamond can be exponentially improved by cutting the stone very well. Cut is often confused with shape, the form into which the diamond is cut. The graphic below illustrates this difference, with the photographic image of the diamond representing shape and the drawings to the left of each detailing the size and positioning of the facets for an ideal cut of each shape. This chart also details some of the most common diamond-cutting problems and mistakes.
| Ideal Cut |
Vert Good Cut |
Shallow Cut |
Deep Cut |
|
|
|
|
| * Arrows indicate light behavior |
A round diamond that has been cut as close to ideal as possible displays a "hearts" pattern when viewed from bottom side up and an "arrow" pattern when viewed from the top. (see below)
|
| THE 4 C'S - COLOR |
Color is one of the more detectable features of diamonds for non-jewelers to observe, although it is impossible for even the most skilled eye to differentiate between loose diamonds fewer than two color grades apart, or three grades apart for a stone that has been set. For this reason, color is almost often denoted with a two or three grade range and gemologists are trained to determine a diamond's color grade using master sets, gems that serve as ideal examples of one color grade.
This chart provides examples of the color grades and ranges as determined by the Gemological Institute of America:
| GIA DIAMOND COLOR CHART |
| Colorless |
Near Colorless |
Faint |
Very Light |
Light |
|
| DEF |
GHIJ |
KLM |
NOPQR |
STUVWXYZ |
Although diamond color grades range from D-Z, it's rare to find jewelry utilizing anything beyond K color, and Eternity Rings and Bands cuts off at H color for most items. Diamonds beyond this color grade steadily decline in rarity and value as they have noticeable yellow or brownish tints. Please note, however, that diamonds with very pronounced natural colors including bright yellows, pinks, and blues are quite rare and often worth substantially more than many types of white diamond.
|
| THE 4 C'S - CLARITY |
The next of the four Cs is clarity, which is the evaluation of a diamond's internal and external flaws. Generally speaking, flaws inside a stone are called inclusions while flaws on the surface are known as blemishes. However, for the purposes of grading, gemological labs refer to all diamond flaws as inclusions.
Clarity grades are divided into the following categories:
| GIA DIAMOND CLARITY CHART |
| FL - IF |
VVS1 - VVS2 |
VS1-VS2 |
SI1-SI2 |
I1 |
I2-I3 |
|
| Flawless-Internally Flawless. |
Very, Very Slightly Included |
Very Slightly Included |
Slightly Included |
|
Imperfect |
|
Imperfect - Inclusions visible to the naked eye |
| Inclusions not visible to the naked eye |
Slightly Visible Flaws |
ERB DOES NOT CARRY |
|
| FL/IF |
Flawless or internally flawless: These diamonds have very minor to no inclusions and are extremely rare. Some may have tiny surface blemishes. |
| VVS1/VVS2 |
Very, very slightly included: These diamonds require a 60x magnification to clearly see inclusions. The inclusions in these diamonds are hard for even a trained grader to see under 10X magnification. |
| VS1/VS2 |
Very slightly included: These diamonds require 30x magnification to clearly see inclusions. These diamonds will be eye-clean. |
| SI1/SI2 |
Slightly included: This grade generally requires 10x magnification to clearly see inclusions. Sometimes very large SI diamonds of the lesser quality grade are not perfectly eye clean. Feel free to call us and our Graduate Gemologist can examine SI diamonds to see if they are eye-clean. SI diamonds offer some of the best values. |
| I1/I2/I3 |
Included: These diamonds are the most likely to have eye-visible inclusions. We do not sell diamonds of the I2 or I3 grades, but we do offer the best quality stones available in the I1 category in order to provide our customers a lower-priced option. In the small gems generally used for pieces like eternity bands, the difference between a very good I1 diamond and an average SI diamond is often negligible.
** Note : Eternity Rings and Bands does not carry I2 or I3 Diamonds. |
| THE 4 C'S - CARAT |
Carat weight, the last of the four Cs and the trait that almost anyone can spot immediately, is the unit of measure applied to diamonds and other gems. Although carats measure weight rather than size, as millimeter width of diamonds with the same weight can vary depending on the shape and cut of the diamond, this graphic gives approximations of what you can expect from round diamonds in assorted carat weights.
|
|
|
0.02 Ct
1.7 mm |
|
0.03 Ct
2.0 mm |
|
0.04 Ct
2.2 mm |
|
0.05 Ct
2.4 mm |
|
0.10 Ct
3.0 mm |
|
0.15 Ct
3.4 mm |
|
|
|
|
|
|
|
|
|
0.20 Ct
3.8 mm |
0.25 Ct
4.1 mm |
|
0.33 Ct
4.4 mm |
0.50 Ct
5.0 mm |
0.60 Ct
5.3 mm |
0.75 Ct
5.7 mm |
|
|
|
|
|
|
|
|
0.90 Ct
6.2 mm |
1.00 Ct
6.4 mm |
|
1.25 Ct
6.9 mm |
1.50 Ct
7.3 mm |
1.75 Ct
7.7 mm |
|
2.00 Ct
8.1 mm |
|
|
|
|
|
|
|
|
2.25 Ct
8.5 mm |
2.5 Ct
8.8 mm |
2.75 Ct
9.1 mm |
3.00 Ct
9.4 mm |
|
3.50 Ct
10.0 mm |
4.00 Ct
10.4 mm |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4.50 Ct
10.8 mm |
|
5.00 Ct
11.0 mm |
5.50 Ct
11.3 mm |
6.00 Ct
11.7 mm |
|
|
7.00 Ct
12.4 mm |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
8.00 Ct
13.4 mm |
9.00 Ct
13.5 mm |
10.00 Ct
14.5 mm |
|
15.00 Ct
16.0 mm |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
In your shopping, you may have noticed that pricing for diamonds of comparable cut, color and clarity grades increases exponentially rather than proportionally with the carat weight of the diamond. This is because finding large, good quality diamonds is less likely than finding small diamonds, or large diamonds that need bad areas cut away to form multiple smaller gems, so the value of a gem increases as the supply of gems like it decreases.
On sites like ours offering diamond pieces with multiple stones, you may notice measurements given in "cttw", which stands for "carat total weight". This is commonly used to describe multi-diamond items with the combined weight of every diamond, as the size and individual weight of an item like an eternity ring will vary based on the finger size. For example, a 3.00 cttw diamond eternity ring in a finger size 5 might be made up of a smaller number of larger diamonds than a 3.00 cttw eternity ring in a finger size 8, the total weight of all the diamonds for either ring remains the same.
|
| DIAMOND SHAPES |
| Round |
Oval |
Asscher |
|
|
|
| Emerald |
Marquise |
Pear |
|
|
|
| Radiant |
Princess |
Heart |
|
|
|
|
| APPRAISALS VS CERTIFICATES |
The key difference between an appraisal and a certificate is that an appraisal determines the monetary value of a loose diamond or an entire piece of jewelry, while a certificate catalogs and makes official the quality rating of a specific loose diamond without assigning a monetary value. All items sold at Eternity Rings and Bands include a free appraisal by one of our GIA graduate gemologists at your request.
 
Certification, sometimes informally called "the fifth C", could be considered a blueprint or biography of a particular diamond. There are a number of gemology labs that certify diamonds, but the GIA, AGS, and to a lesser degree the EGL are regarded as the most reputable and precise.
While Eternity Rings and Bands does not stock items with certified diamonds, the higher carat weight rings may be available with certified diamonds at the customer's request. If you are interested in a custom ring including GIA certified stones, call our office at 1-877-472-2700.
|
| WHAT IS A DIAMOND? |
Diamonds are formed by carbon atoms that, after being subjected to intense heat and pressure within the earth over a long period of time, crystallize into a specific arrangement. Diamonds have many particular characteristics that make them special; in addition to their unusual beauty, diamonds are the hardest naturally-occurring material on Earth. The Mohs scale (see below), used to measure the hardness of different substances, is a 1 to 10 scale with talc rating a 1 and diamond representing 10. The next hardest substance is corundum, which is the main component comprising rubies and sapphires. However, with a rating of 9, corundum is significantly behind the diamond on this scale.
| MOH'S HARDNESS SCALE |
 |
|
|
)
)
