The 4 C’s

The 4Cs are used throughout the world to classify the rarity of diamonds. Diamonds with the combination of the highest 4C ratings are more rare and, consequently, more expensive. No one C is more important than another in terms of beauty and it is important to note that each of the 4Cs will not diminish in value over time.


Dallas Diamonds diamond cut chartRefers to the angles and proportions of a diamond.

Based on scientific formulas, a well-cut diamond will internally reflect light from one mirror-like facet to another and disperse and reflect it through the top of the stone. The result is a display of brilliance and fire; thereby well-cut diamonds are priced higher than deep or shallow-cut diamonds. Diamonds that are cut too deep or too shallow lose or leak light through the side or bottom, resulting in less brilliance and ultimately, value.

Cut also refers to shape—round, square, pear, or heart for example. Since a round diamond is symmetrical and capable of reflecting nearly all the light that enters, it is the most brilliant of all diamond shapes. Non-round shapes, also known as “fancy shapes,” will have their own guidelines to be considered well cut.


Dallas Diamonds diamond colors chartRefers to the degree to which a diamond is colorless.

Diamonds range in color from icy winter whites to warm summer whites. Diamonds are graded on a color scale established by the Gemological Institute of America (GIA), which ranges from D (colorless) to Z.

Warmer colored diamonds (K–Z) are particularly desirable when set in yellow gold. Icy winter whites (D–J) look stunning set in white gold or platinum.

Color differences are very subtle and it is very difficult to see the difference between, say, an I and an J. A controlled lighting condition is used to grade the color of a diamond with the help of a master set for accuracy.

Truly colorless stones graded D are treasured for their rarity.


Dallas Diamonds diamond clarityRefers to the presence of inclusions in a diamond.

Inclusions are natural identifying characteristics such as minerals or fractures, appearing while diamonds are formed in the earth. They may look like tiny crystals, clouds or feathers.

These inclusions can be viewed by a magnifying loupe. This tool allows you to see a diamond at 10x its actual size so that inclusions are easier to see. The position of inclusions can affect the value of a diamond. There are very few flawless diamonds found in nature, thus these diamonds are much more valuable.

Inclusions are ranked on a scale of perfection, known as clarity, which was established by the Gemological Institute of America (GIA). The clarity scale, ranging from F (Flawless) to Included (I), is based on the visibility of inclusions at a magnification of 10x.

Some inclusions can be hidden by a mounting, thus having little effect on the beauty of a diamond. An inclusion in the middle or top of a diamond could impact the dispersion of light, sometimes making the diamond less brilliant.

The greater a diamond's clarity, the more brilliant, valuable and rare it is.


Dallas Diamonds diamond weight in caratsRefers to the weight of a diamond.

Carat is often confused with size even though it is actually a measure of weight. One carat is equivalent to 200 milligrams. One carat can also be divided into 100 “points.” A .75-carat diamond is the same as a 75-points or 3/4 carat diamond.

A 1-carat diamond doesn’t costs exactly twice the price of a half-carat diamond, since larger diamonds are found less frequently in nature, which places them at the rarest level, a 1-carat diamond will cost more than twice a 1/2-carat diamond (assuming color, clarity and cut remain constant). Cut and mounting can make a diamond appear larger (or smaller) than its actual weight.

The 5th C: CRYSTAL

Dallas Diamonds diamond crystal roughRefers to the material the diamond is cut from.

The overlooked 5th C is just as important as any other.  The crystal or rough the polished diamond comes from determines the transparency and to some degree the luster of the cut & polished diamond.  This explains why some diamonds are cloudy, milky or just ugly compared to a diamond cut from better quality rough.

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