Diamond Education

Welcome to “Diamonds 101.” Century Diamonds is committed to helping customers make educated, informed decisions, and here you can find all the information you need for the 4 C’s: Clarity, Color, Carats and Cut. If you have any questions, feel free to visit our Contact Page and ask us anything.

Diamond Clarity
  • FL-IF  ·Flawless or Internally Flawless. No internal inclusions that can be seen under 10x magnification. May be seen under larger magnification
  • VVS1-VVS2  ·Very Very Small inclusions. Difficult to detect under 10x magnification.
  • VS1-VS2  ·Very Small inclusions can be seen under 10x magnification and in rare cases to the naked eye.
  • SI1-SI2  ·Small inclusions can be seen under 10x magnification and may be visible to the naked eye. Inclusions will be visible on larger diamonds.
  • SI3  ·Inclusions can be seen under 10x magnification and are visible to the naked eye. Slight cloudiness.
  • I1-I2-I3  ·Inclusions are visible under 10x magnification and visible to the naked eye. Diamonds will be cloudy.

Diamond clarity refers to the visual quality of the diamond, based on the amount of inclusions and blemishes. Inclusions may refer to foreign crystals within the transparent surface of the diamond, or small structural imperfections like cracks. Substantial inclusions can cause diamonds to have a milky or cloudy appearance. Blemishes, on the other hand, are imperfections that appear on the outer surface of the diamond. A clarity grade is assigned based on the appearance of the diamond under 10x magnification.

Smaller inclusions do not typically impact the ability of light to pass through a diamond, but large inclusions can prevent light from transmitting properly. The most valuable diamonds are referred to as Flawless (FL), because they have absolutely no inclusions or blemishes. Such diamonds are rare and coveted.

Overall, there are 10 clarity grades that a diamond can receive. Below FL is IF, or Internally Flawless, followed by Very, Very Small Inclusions (VVS1 and VVS2), Very Small Inclusions (VS1 and VS2), Small Inclusions (SI1 and SI2) and Imperfect (I1, I2 and I3).


Diamond Color Guide

In order to assign a color grade to a particular diamond, a grader must compare the diamond to a master stone diamond set. Each master stone in a particular set exhibits the least amount of color allowed by a diamond of its particular grade. A diamond is assigned a grade based on having more, less or equal color to the master stones.

A chemically perfect diamond has no color at all, but in some cases, color can increase the value of a diamond, even though the colors emerge as a result of chemical impurities and structural defects. Possible colors include yellow, pink, purple, blue or even black. Red diamonds are the rarest and are extremely valuable. 

For standard diamonds, color is graded on an alphabetical scale from D to Z. A “D” to “F” grade represents a perfectly colorless diamond,  while an “S” to “Z” grade represents light yellow. Other grades include “Near Colorless” (G-J), “Faint Yellow” (K-M) and “Very Light Yellow” (N-R).


Diamond Carat Size Chart

Carat refers to the weight of the diamond. Specifically, a carat is a unit of measurement equal to 200 milligrams. Heavier diamonds are more valuable because they appear much less frequently in nature, which makes them scarce and highly desirable. Carats are assessed not only by weight, but also by points. One carat is equal to 100 points, so a .5-carat diamond is equal to 50 points, and a 2-carat diamond is worth 200 points.

Greater weight amounts not only to greater value, but it also allows for greater detail and brilliance. Light has a much larger canvas for refraction on a 2.50-carat diamond than on a .10-carat diamond, and the details are more readily visible and prominent. While a 2.50-carat diamond ring boasts a magnificent appearance, diamonds can actually be more than 100 carats in mass, such as the famous Paragon.


Diamond Cut Shape Chart

The cut refers not to the shape of the diamond specifically, but to the actual quality and precision of the stone. Factors like symmetry, proportion and polish are crucial in assigning a grade to a diamond’s cut. A diamond with high-quality cut will appear more brilliant and luminous, while a poorly cut diamond may appear dull. Many different cuts exist, including the Princess, the Emerald, and the popular Round Brilliant, which contains 58 individual facets and is the most valuable cut.

Diamond Cut Chart

To break it down a bit more, the dimensions and symmetry of a diamond largely define the cut. When a diamond’s facets are in proper alignment, light is more effectively refracted through the top of the diamond. This causes the entire stone to sparkle brilliantly. Most gemologists agree that the cut is the most important characteristic in determining the quality of a diamond, because even if the weight, color and clarity have high grades, a poorly cut diamond will still appear dull, undermining the other characteristics.

When assessing the dimensions of a diamond and how they play a role in defining the cut, it’s important to understand how the wrong dimensions can have an adverse effect on quality. If the stone is too shallow, it loses light through the bottom. If the stone is too deep, it loses light through the sides. Finding the right balance ensures the maximum sparkle. 

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