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Diamond Education

While every diamond is unique, all diamonds share certain structural features. A diamond’s anatomy, or its basic structure, determines its proportions, brilliance, dispersion and scintillation. Each part of the diamond has a specific name, and having a basic understanding of how each part contributes to the diamond as a whole will help you find your perfect diamond.


The design and craftsmanship of the diamond considers weight ratio (weight of the diamond relative to its diameter), the diamond's girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

GIA anatomy of a diamond - weiss jewelers

Cut is oftentimes confused with the shape of the diamond but cut refers to a stone’s facet arrangement. Shape refers to the outline of the stone.

The most common diamond shape used in jewelry is round, as seen in the standard round brilliant cut. All other diamond shapes are known as fancy shapes. Traditional fancy shapes include the marquise, pear, oval and octagonal (as seen in the emerald cut). Square, cushion (square with rounded edges), triangle, and a variety of other shapes are also gaining popularity in diamond jewelry.

diamond shapes - weiss jewelers

One carat equals to 0.2 grams or 200 milligrams. Carat weight is the prime factor that determines the weight of a diamond. Larger diamonds are undoubtedly costlier. Carat makes expressing diamond weight easier as compared to milligrams. Instead of giving three labels to diamonds weighing 20 milligrams, 211 milligrams and 220 milligrams, carat offers a category for fitting the diamonds in a one category, placing these diamonds in one-carat range.

One should not forget that high carat weight does not necessarily mean a larger looking diamond. Even diamonds of the same weight can differ on a basis of other factors, especially cut that influences perceived size. Large diamonds are rare to find and much in demand as compared to small diamonds even of the same quality. The price of a one-carat solitaire diamond ring is more than a ring with smaller diamonds making up the same carat weight. Diamond comparison is not effective until you compare the diamonds of similar features and qualities. While comparing the value of different diamonds, divide cost of every diamond in accordance with the carat weight and then calculate its price per carat.


Diamond clarity means finding out characteristics of a diamond, including the blemishes and inclusions. If you consider the pressure that a diamond is created, and that they are not produced in sterile laboratory, you will be not be surprised to find that most of these diamonds are not free of flaws.

Usually there are two kinds of flaws found in diamonds – blemishes and inclusions. Inclusions are naturally occurring internal flaws that are found in diamonds including cracks, air bubbles, and mineral. However, most blemishes occur at the time of cutting process. The diamonds that have less blemishes and inclusions are considered valuable as compared to those that have more.

GIA certificates consist of a diamonds inclusion plot, as there is no similarity between two diamonds. The plot of the GIA certificate ensures the worth of the diamond you are planning to buy. It lets you have the assurance that the diamond you are receiving is the one you have paid for. If you are in a fix about what clarity grade you should choose, flawless is the best and rarest clarity grade.


While the jeweler talks about the diamonds color, he is referring to the absence and presence of the color in the diamond. Color of a diamond is a result of diamond’s composition and does not change with time. Colorless diamonds allow light to travel through them as compared to the colored diamonds. These diamonds also emit more fire and sparkle. The process, through which a diamond is formed, is the deciding factor for its color. The whiter the diamond is the higher value it will have.


For grading the color of diamonds, jewelers refer to GIA’s color scale that starts the rating with D for the colorless diamonds and grows up to Z as the traces of light yellow or brown color are found in the diamond. Diamonds graded from D to F are amongst the most desirable and valuable stones. These diamonds are a delight for the diamond lovers. Nevertheless, if you have a low budget, you can also find good diamonds with lower grades. These diamonds are not exactly colorless but show no color to untrained eye.

diamond color - weiss jewelery

People often confuse diamond shape with diamond cut. Shape of the diamond is the outward appearance. When the diamond jewelers use the word cut, they are referring to reflective qualities of the diamond not their shape. Quality of diamond cut is a crucial part of 4Cs of diamonds. A great cut provides brilliance to the diamond. Finish and angles of all the diamonds lets you determine the diamond’s ability to handle light that results in its brilliance.

When a diamond has a good cut, light travels through it easily, adding to its spark. The light that is passed through the diamond because of cut is alone responsible for making the diamonds shine and increase their desirability. If a diamond is not cut properly, light enter through the table after reaching the facets, it leaks out from bottom or side, cutting down its brilliance.

diamond cut - weiss jewelers

Good Cut diamonds reflect most of the light that passes through them. The proportion of these diamonds is outside the preferred range. Diamonds that fall under this category will allow you save money without compromising on beauty and quality of the diamond. Fair and Poor quality diamonds reflect very little proportion of light that is entered to them. These diamonds are cut in order to increase carat weight above all the other considerations.

Proportion – Understanding Brilliance, Dispersion & Scintillation

Well–proportioned diamonds exhibit three different properties: brilliance, dispersion and scintillation. As light strikes a diamond's surface, it will either reflect off the table of a polished stone or enter the diamond. The light that is reflected is known as the diamond's brilliance — the flash of white light one sees when looking at a stone. As light travels through a stone, some of the light rays are separated into flashes of color. This is known as dispersion. The result of dispersion—the separation of white light into its spectral colors — is known as fire. Scintillation is flashes of color that are viewable as an observer moves a diamond back and forth.

Diamond Polish

Diamond polish influences how well light is able to pass through a diamond. It is a very important attribute in determining a diamond's overall brilliance. When choosing a diamond, it is best to pick one that is laboratory certified with good, very good or excellent polish. Diamonds with poor polish are significantly less brilliant because they have microscopic polish lines that blur the surface of the stone—this also reduces the amount of light that enters or exits the diamond. Be aware that many diamonds have a poor polish because some diamond cutters reduce their costs by not spending sufficient time to properly polish a diamond.

diamond polish - weiss jewelers

Polish is graded the same that way symmetry is graded. On a GIA report, the grades are Excellent, Very Good, Good, Fair or Poor. The same applies for AGS and IGI reports, which also include ideal in their list.

  • EX or E - Excellent, Flawless at 10X magnification

  • VG or VGD - Very Good, Extremely difficult to locate under 10X magnification

  • GD, GO, G - Good, Very difficult to see under 10X magnification

  • F, FR, FA - Fair, Noticeable under 10X magnification

  • PR, PO, P - Poor, Easy to see under 10X magnification / Visible to unaided eye

  • VP, VE - Very Poor, Relatively easy to see with the unaided eye

  • EX or EP - Extremely Poor, Obvious to see with unaided eye


There is very little difference between these ratings to the unaided eye. A diamond with a polish rating of Good can still be a remarkable stone. It is only under magnification that the differences in these ratings become clearer. Polish rated Fair (FR) and Poor (PR), however, indicates that the flaws in the polish are visible to the naked eye and affect the overall beauty of the diamond.

It is also important that your ring does not have a porosity problem or rough spots in the metal. Porosity is when there are little surface holes that get worse as you go deeper into the metal. Generally the result of mass producing rings with poor quality control, porosity makes a ring weak and is non-repairable. A ring with porosity will eventually break down.

Diamond Fluorescence

Fluorescence is a naturally occurring phenomenon that appears in certain minerals and gems. Some quality diamonds display a visible light when they are exposed to ultraviolet light. This light is known as fluorescence. Under most lighting conditions, a diamond's fluorescence is not visible to the naked eye, although the diamond will exhibit a soft colored glow if held under an ultraviolet lamp.

Not all diamond fluoresce. If a specific diamond does not fluoresce, the grading report will list the diamond's fluorescence as either inert or none.

diamond fluorescence - weiss jewelers

There are different types of diamond fluorescence.  The degree of fluorescence varies from faint to medium to strong to very strong. Faint means that the stone has a slight glow that is difficult to see under ultraviolet light. Very strong means that the diamond emits a deep glow that is very clear under ultraviolet light. The color of the fluorescence can also vary, although blue is the most common color. Yellow, green and white are other colors that a fluorescent diamond may exhibit.


How Does Fluorescence Affect A Diamond?

Fluorescence usually has no effect on a diamond's appearance in regular lighting conditions. In some cases, however, a strong blue fluorescence can make a yellow colored diamond appear whiter. In rare cases, it can or cause a stone to appear milky or oily.