The Larger a Diamond, the More Rare

Larger diamonds are found relatively infrequently in nature, which places them at the rarest level of the Diamond Quality Pyramid. What also makes a bigger diamond so desirable is that it shows off a stone's fine color and cut, and therefore its brilliance, to its best advantage.

A diamond's size is measured in carat weight, and each carat is equal to 100 points. A .75 carat diamond is the same as a 75-point diamond or a 3/4 carat stone.

While larger diamonds are highly prized, diamonds of equal size may vary widely in value and brilliance, depending on their qualities of clarity, cut, and color.


The Purer a Diamond, the More Brilliant

The greater a diamond's clarity, the more brilliant, valuable and rare it is -- and the higher it is on the Diamond Quality Pyramid.

Virtually all natural diamonds contain identifying characteristics, yet many are invisible to the naked eye. Under the scrutiny of a jeweler's 10x-magnifying loupe or microscope, natural phenomena -- called inclusions -- may be seen. These are nature's birthmarks, and they may look like tiny crystals, clouds, or feathers.

Diamonds categorized as internally flawless reveal no such inclusions. Flawless stones are at the peak of the Diamond Quality Pyramid and are treasured for their rarity and beauty. Diamonds with very, very small inclusions are graded as VVS1 or VVS2. The larger the inclusion, the lower the grade and the less rare the diamond. Inclusions that can be seen with the naked eye are graded I1 to I3.

The number, color, type, size and position of surface and internal birthmarks affect a diamond's value. Major inclusions can interfere with the path of light that travels through a diamond, diminishing its brilliance and sparkle and therefore its value.

The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.

Flawless (FL) - No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) - No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) - Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2) - Inclusions are clearly visible under 10× magnification but can be characterized as minor
Slightly Included (SI1 and SI2) - Inclusions are noticeable to a skilled grader using 10× magnification
Included (I1, I2, and I3) - Inclusions are obvious under 10× magnification and may affect transparency and brilliance


The More Pure the Color in a Diamond, the More Rare

Diamonds are graded by color, starting at D and continuing through the alphabet. Truly colorless stones, graded D, treasured for their rarity and value, are highest on the Diamond Quality Pyramid.

While many diamonds appear colorless, they may actually have subtle yellow or brown tones and these color grades include P and Q. Although still beautiful, they will be less rare and therefore less valuable. To appreciate the simple beauty of each individual stone, you should compare diamonds side by side with a jeweler.

"Fancy" diamonds -- in well defined colors that include red, pink, blue, green and canary yellow -- are highly prized and particularly rare.



The Better Cut a Diamond, the More Brilliant

A well cut or faceted diamond, regardless of its shape, scintillates with fire and light -- offering the greatest brilliance and value.

While nature determines a diamond's clarity, carat weight and color, the hand of a master craftsman is necessary to release its fire, sparkle and beauty. When a diamond is cut to good proportions, light will reflect from one mirror-like facet to another and disperse through the top of the stone, resulting in a display of brilliance and fire.

Diamonds that are cut too deep or too shallow lose light that spills through the side or bottom. As a result, poorly cut stones will be less brilliant and beautiful -- and certainly less valuable -- than well cut diamonds higher on the Diamond Quality Pyramid.

Diagram of Diamond Cutting Process.

Diamond Proportions and Definitions

Depth Percentage - The depth of a stone is measured from the table to the culet. It is expressed as a percentage of the stone's diameter at the girdle.

Table Size - The size of the table of a fashioned diamond is measured as a percentage of the stone's narrow-girdle diameter. On a round brilliant, it is measured from corner to opposite corner, rather than from flat side to flat side.

Ratio- The ratio is referred to the overall proportions of the diamond from Length to Width .

Girdle - The girdle is a narrow section of the diamond dividing the crown from the pavilion. The girdle's outer edge, is the portion that is usually grasped by the setting or mounting.

Culet- The culet is a facet placed at the tip of the bottom pavilions a culet is a flat face on the bottom of a diamond, the culet is added to protect and prevent damage to the pointed tip.

Diamond Proportions and Definitions Diamond Proportions and Definitions


Diamond Fluorescence

In some cases of diamonds especially in the higher colors, the presence of strong fluorescence creates an appearance that is described as hazy, milky, oily, or cloudy. For this reason, strong fluorescent diamonds can be valued and are trading at lower that similar diamonds with fluorescent ratings of "none," "faint," or "medium."

Every certificate rates diamond fluorescence according to the following scale: 

  • None, Nil, Negligible = no fluorescence, no influence on color
  • Faint Blue, Slight = weak fluorescence, almost no significant influence on color
  • Medium Blue = average fluorescence, some influence on color
  • Strong Blue=strong influence on color especially in the higher
  • colors D-H
  • Very Strong Blue= very strong influence on color, in many cases hazy, oily, cloudy, or milky type of look


An Occasion Worth Celebrating

Now that you understand why some diamonds are more rare than others, you can make an informed decision. Choose a beautiful stone that combines the qualities of the 4Cs you most value. Then you're ready to give the most enduring gift of love. Born of the earth, reborn on the woman you love, this diamond is more than a precious gem and all that it symbolizes ... it's a piece of forever.