Cut is the human contribution to a diamonds beauty, brilliance and fire. The way a diamond is cut can affect the other three C's which are dictated by nature. Even if the diamond has perfect color and clarity a diamond that has been cut poorly will appear dull and lifeless. One of the factors that make a diamond so rare and special is its ability to display a unique fire and brilliance.

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When the carbon is compounding to create the diamond, if natural gasses enter through the stone as it is forming it will change the color saturation, leaving traces of color within the stone. Due to the effects of nature you would expect all stones to have some trace of color within. Diamonds color is graded on a letter scale beginning with D (colorless) and moving through the alphabets to Z. A single increase or decrease in the color grade can make a price difference of thousands of dollars, depending on the size of the diamond.


Most diamonds contain minute traces of non-crystallized carbon in internal stress factors. Called inclusions, most of these are not apparent to the naked eye but can be seen under magnification. Perfect clarity means that no inclusions are discernible when the diamond is examined under a 10x magnification lens. Inclusions greatly effect the beauty and value of a diamond because they absorb the light rather than allowing it to be reflected back through the front side of the stone. How much they reduce the value of a diamond depends on their size, number and position throughout the stone. An inclusion in the center of the diamond beneath the table is more visible than one near the edge. The inclusion may also be mirrored many times by adjoining facets.

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Clarity Grade Description
No internal or external flaws.
Internally Flawless
No internal flaws, slight external blemishes.
Very, Very Slight Inclusions
Very difficult for a professional to see under 10X magnification.
Very Slight Inclusions
Difficult for a professional to see under 10X magnification.
Slight Inclusions
Easy for a professional to see under 10X magnification, might be visible to the naked eye.
Inclusions are visible to the naked eye.


The weight of a diamond is measured in Carats. 1 Carat equals 0.2 gram and there are 100 points to a carat. Thus a 50 point diamond is half a carat (0.50ct) and weights 0.1 gram. A Grain, no longer used, is accepted to be 0.050 grams. Many dealers still use the terms a grainer meaning 0.25ct, two grainer - half carat, six grainer- 1.5 carats etc.

There is an approximate relationship between weight and diameter of a round brilliant cut diamond. This is useful when trying to estimate the size of a diamond.

Weight Size (diameter) Weight in pts Weight in fractions
0.05ct 1.00mm 5pts 1/20th
0.10ct 3.00mm 10pts 1/10th
0.20ct 3.85mm 20pts 1/5th
0.25ct 4.10mm 25pts 1/4
0.33ct 4.55mm 33pts 1/3rd
0.40ct 4.80mm 40pts  
0.50ct 5.15mm 50pts 1/2
0.66ct 5.72mm 66pts 2/3
0.75ct 6.00mm 75pts 3/4
0.90ct 6.40mm 90pts  
1.00ct 6.65mm 100pts 1 carat
1.50ct 7.50mm 150pts 1 1/2
2.00ct 8.10mm 200pts 2 carat