USA Jewels
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Diamond Buyers Guide

  • Cut
  • Color
  • Clarity
  • Total Weights
  • Symmetry
  • Shape
  • Polish

The Four C's of Diamonds

Fine diamonds are among the most coveted of all gems. Their value, however, differs widely from one diamond to another. Experts evaluate every diamond for rarity and beauty, using four primary guidelines. These are called The Four C's - Cut, Color, Clarity, and Carat Weight.

Rarity and Beauty All gem-quality diamonds are rare, taking billions of years for nature to form them. The journey from the mine to you is long and arduous. While the four C's information helps you to identify the quality of the diamond you are purchasing, it is the combination of these four characteristics which determine a diamond's rarity. If you imagine a four-sided pyramid, with each side being a diamond characteristic - the more readily available diamonds form the base of the pyramid while the rarest diamonds are at the top. Keep this pyramid in mind when you are selecting your diamond. Your selection of characteristics will determine rarity and value. And remember-beauty is in the eye of the beholder. A diamond can only be truly perfect if you think it is beautifully perfect for you.

Diamond's Cut

When you think of the cut, you probably think of the shape of the diamond. You are partially correct. While cut does refer to shape, it also refers to the proportions of how the diamond is actually cut.

Diamonds are cut into many different shapes, reflecting not only popular taste but the proportions and quality of the rough diamond. The most popular shapes include Round, Oval, Square, Princess, Emerald, Baquette, and Marquise cuts. Many specialty shapes are also available.

A diamond's overall proportions, as well as the size and placement of its many reflective surfaces or facets, also play a large part in "cut." The consistency and balance of these can greatly affect how the stone captures light and reflects it back to the eye.


Diamond's Color

With the exception of some fancy colored diamonds, the most valuable diamonds are those with the least color. The color scale for transparent diamonds runs from D-F (colorless), G-J (near colorless), K-L (faint yellow), to Z (light yellow). Completely colorless diamonds are rare.

When diamonds are formed with traces of other minerals, rare and beautiful colors can result. These "fancy" colors range from blue to brilliant yellow to red, brown, pale green, pink, and violet. Because of their rarity, colored diamonds are highly desirable and may be quite valuable.

Diamond's Clarity

A diamond's clarity is measured by the existence, or absence, of visible flaws. Tiny surface blemishes or internal inclusions -- even those seen only under magnification with a jeweler's loupe -- can alter the brilliance of the diamond and, thus, effect its value. Clarity levels begin with Flawless (F & IF) and move down to Very Very Slight (VVS1 & 2), Very Slight (VS1 & 2), Slightly Included (SI1 & 2), and Included (I1, 2 & 3).

Diamond Clarity Gradings

These diamond clarity gradings are presented from best to least.

FL,IF Clarity

Flawless: No internal or external flaws Internally Flawless: No internal flaws.

VVS1,VVS2 Clarity

Very, Very Slightly Included: Very difficult to see inclusions under 10% magnification.

VS1,VS2 Clarity

Very Slightly included: Inclusions are not typically visible to the unaided eye.

SI1,SI2 Clarity

Slightly included: Inclusions are visible under 10x magnification and may be visible to the unaided eye.

I1,I2,I3 Clarity

Included: Inclusions are visible with the unaided eye.


Diamond's Total Weight

The size of a diamond is measured, not by its dimensions, but by weight. One carat, the traditional unit of measure for diamonds, is equal to approximately 0.2 grams. You may also hear the weight of a diamond referred to in points. A point is equal to 1/100 of a carat; therefore, a 75-point diamond equals 0.75 carat. Diamonds of equal weight may appear slightly different in size, depending on their depth and proportions. Because they are quite rare, larger diamonds of gem quality are much more valuable. .

Diamond Diamond
Diamond Diamond

Diamond's Symmetry

Diamond Symmetry is perhaps the most important aspect to a diamond's beauty. It is the heart of its radiance and fire. It is what makes customer stop and stare at a piece of jewelry because it is what generates the love for diamond. A diamond's symmetry is what determines how much light can be reflected through all it facets. In technical terms it refers to how accurately the facets align and intersect. Factors that deter light exposing that radiance are extra or misshapen facets, off center culets and table or wavy girdles. Rough diamonds have many natural defects so diamond cutters will purposely push for a minor imperfection in symmetry to allow for a balance when finished. When certifying a diamond, symmetry is shown to rank from Poor-Excellent.

Symmetry also has an impact on the price of the stone. A diamond that has excellent symmetry and excellent polish is generally more expensive than a good-fair ranking in both categories. It is perceived to have higher value and lower noticeable defects.

Every USA Jewels Diamond or third party certificate diamond will display the symmetry grade, using the following scale:

Symmetry Grade Description
Excellent No symmetry defects visible under 10x magnification.
Very Good Any defects are very difficult to see under 10x magnification.
Good Any defects are difficult to see under 10x magnification.
Fair Defects are noticeable at 10x magnification, and may be visible to the unaided eye.
Poor Defects are visible to the unaided eye.

Diamond's Shape

No two diamonds are alike. They are distinct by their color, cut, shape, size and many other physical characteristics. Diamond shape is one of the more easily identifiable characteristics of a different stone. Diamond shape starts from the diamond rough and then it is cut from the original shape into the more desirable one. Round diamonds are generally the most popular and desired which leads to a higher cost for them. Below are the various diamond shapes we offer here at USA Jewels.

Round Cut Princess Cut Emerald Cut Asscher Cut Marquise Cut Oval Cut Radiant Cut Pear Shape Heart Cut Cushion Cut

Anatomy of a Diamond


Every diamond will have a distinct set of properties and proportions that define its anatomy. The below guide will help you identify these areas:

Name Description
Crown The top part of a diamond extending from the table to the girdle.
Culet The small or pointed facet at the very bottom of a polished stone.
Depth The total height of a diamond as measured from the table to the culet.
Diameter Width of a polished stone that is measured from edge to edge.
Girdle The very edge of the diamond where the crown and pavilion meet.
Pavilion The underside of a diamond extending from the girdle down to the culet.
Table Largest polished facet located on the top portion of the diamond.
USA Jewels

Diamond's Polish

The definition of the Diamond Polish is simple the overall state of the surface of a diamond that has been finished. The rating for diamond polishing is placed based on the amount of polishing lines that can be seen. The lines are located there due to small diamond crystals which are stuck to the polishing wheels that are used by diamond cutters. This process is done after the cutting. The polish is very important because it determines the degree of light that can pass through a diamond. That is what is defined as the diamond brilliance. All lab certified diamonds report polish from a range of Poor-Excellent similar symmetry. The lower the polish gives a diamond less brilliance which decreases the value and desire of the stone. Below are the five ratings given to Diamond Polish.

Polish Ratings

Excellent and Very Good have no noticeable difference so when choosing a diamond, the customer can get away with polishing. But when you push down to Fair and Poor the polishing is very noticeable and should be avoided if your budget allows for it.

Polish Grade Description
(EX) Excellent Not visible.
(VG) Very Good Not visible to an unaided eye.
(G) Good May be visible to an unaided eye.
(F) Fair Visible to an unaided eye.
(P) Poor Visible to an unaided eye.