4 C’s of Engagement Rings

The 4 C’s are a set of standards that let people evaluate and compare the quality of a diamond. The 4 C’s are Carat, Color, Clarity and Cut. The standards are set by the Gemological Institute of America (GIA) and the American Gem Society (AGS).


This has nothing to do with a “karat,” as in 18K gold. Instead, diamonds are weighed in metric carats.  One carat is equal to 0.2 grams, about the same weight as a paperclip.


The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or light yellow or brown. Each letter grade has a clearly defined range of color appearance.


Clarity is determined by the inclusions and blemishes of a diamond.

(AGS 0)
Flawless and Internally Flawless

Flawless: No inclusionsor blemishes of any sort under 10X magnification.

Internally Flawless: No inclusions, but some minor blemishes.

(AGS 1-2)
Very Very Slightly Included

Contains minute inclusions that are very difficult to see under 10X magnification, even for an experienced grader.

VS1 – VS2
(AGS 3-4)
Very Slightly Included

Contains minute inclusions when observed with effort under 10X magnification.
An excellent value as there is no noticeable difference to the unaided eye from VVS.

SI1 – SI2
(AGS 5-6)
Slightly Included

Contains inclusions noticeable under 10x magnification. An SI1 should not have any eye visible inclusions, but SI2 may, depending on the size and location of the flaws.

I1 – I2 – I3
(AGS 7-8-9)

Contains inclusions that are obvious under 10X magnification and possibly to the unaided eye.


The cut of any diamond has three attributes: brilliance (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the flashes of light, or sparkle, when a diamond is moved).

An understanding of diamond cut begins with the shape of a diamond. The standard round brilliant is the shape used in most diamond jewelry. All others are known as fancy shapes. Traditional fancy shapes include the marquise, pear, oval and emerald cuts. Hearts, cushions, triangles and a variety of others are also gaining popularity in diamond jewelry.

Other Less Important Characteristics


Polish refers to the quality of the diamond’s surface and includes such features as nicks, polish lines, and abrasions.


Symmetry of a diamond refers to the exactitude of the shape and alignment of the facets.


The depth of a diamond is measured from the table to the cutlet. It is expressed as a percentage of the stone’s diameter at the girdle.


Table percentage of a diamond is expressed as a percentage of the stone’s narrow-girdle diameter. On a round brilliant diamond, it is measured from the corner to the opposite corner rather than from flat side to flat side.


Fluorescence is different from a diamond’s color and refers to the diamond’s ability to fluoresce under ultraviolet light.

The fluorescence of a diamond is defined by its intensity as None, Faint, Medium, Strong, or Very Strong.


The length to width ration is a comparison of the length and width of fancy shaped diamonds. It shows how long or wide a diamond appears when viewed from the top.



Categories: Rings

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