The Essentials You Need To Know When Purchasing and Caring For Your Diamond.
Diamond Glossary


The phenomenon of brilliance in diamonds occurs when white light captured from all the surfaces of the diamond is reflected upwards through the top. The most abundant brilliance is attained when a diamond is well cut with accurate proportions.

Brilliant Cut:

A brilliant cut has triangular facets that surround the stone and culminate with a flat top. Faceting arrangements are calculated for maximum brilliance, sparkle and beauty. A brilliant cut can be round, marquise, oval, pear-shaped, heart-shaped, princess (square), or radiant. With 57 or 58 facets, the round brilliant cut is currently one of the most popular styles of diamond cutting.

Carat Weight:

The measuring unit for the weight of a diamond is carat. One metric carat is exactly 200 milligrams or 1/5 gram. The origin of the word carat is from the carob seeds that were used to balance scales in antiquity.


Diamonds have small imperfections in them called inclusions. The more inclusions there are in a diamond, the lower the clarity and the less valuable the diamond will be.


A cloud is a hazy area within the diamond made up of many small white crystals that cannot be observed individually. This phenomenon may be local or it may extend all through the diamond. This phenomenon negatively affects the brilliance of a diamond; numerous clouds in a diamond or very large clouds can significantly reduce the brilliance.


The color of a diamond is perceived as a critical factor that determines the overall beauty of a diamond. Colorless diamonds are the most desirable and the most valuable.
The customary color grade system is comprised of letters from D to Z. For the best color, which is almost clear white, the letter grade D will be given. Following the alphabet down to Z, a commensurate degrading occurs from colorless toward yellow or brown tints, where the letter grade Z will be given to a diamond of yellow color.


The culet is the pointed base of the diamond where the facets of the pavilion converge. In many cases, this point actually has a very small facet. The culet is referred to in terms that relate to the presence or size of this facet. The grades of the culet are: None, Pointed, Very Small, Small, Medium, Slightly Large, Large, Very Large, and Extremely Large. A smaller culet is more fashionable.


The cut of a diamond refers to the symmetry and the proportions of the diamond. The cut gives the diamond its sparkle. Using the measures of proportions and angles of a diamond, experts calculate the light presentation of a diamond. There are many diamond shapes to choose from and choosing the right shape of a diamond is largely a matter of proclivity and style. No matter what shape and quality one may prefer, a Laboratory Report should accompany one's engagement ring or any significant diamond purchased.

Ideal Cut:

The Ideal Cut is the highest cut grade for diamonds. The proportions of such a diamond allow for maximum brilliance and produce the most beautiful sparkle. Those who prefer premium quality will enjoy such a diamond. Only round diamonds are included in the Ideal Cut category.

Excellent Cut:

The Excellent Cut is a cut grade slightly lower than the Ideal Cut. Such a diamond is almost as brilliant as an Ideal Cut. The polish and the symmetry are EX-VG, while the price is relatively lower.

Very Good Cut:

The Very Good Cut offers a diamond that is cut to exact proportions and thus reflects most of the light that enters it. Such a diamond creates a fair amount of brilliance but a small amount of light may still 'leak' from the bottom of the diamond. In addition, the large table size of a Very Good Cut results in less dispersion or 'fire' than that of an Ideal Cut. In the case of Very Good Cut diamonds, the cutter chose to stray slightly from the preferred proportions in order to create a larger diamond with an increased level of clarity. Therefore, some will find the table size and the girdle width of such diamonds not to their liking. Generally, the price of a Very Good Cut is lower than the price of an Ideal Cut.

Good Cut:

The Good Cut diamond is cut to such proportions that produce abundant sparkle, while its price is lower than the price of a Very Good Cut diamond. Diamond cutters may choose the proportions of a Good Cut in order to create the largest possible diamond from the original rough crystal without sacrificing carat weight. A Good Cut diamond might have a slightly smaller or larger table facet than an Ideal Cut diamond. Good Cut diamonds reflect most of the light that enters them and they offer an excellent value for those who are looking for an affordable diamond without having to sacrifice size or color. 


The crown is the top portion of a diamond, from the girdle (the thickest part around the stone) to the table (the top surface facing the viewer).

Crystal Growth:

A small crystalline growth within the diamond; a crystal growth looks like a small diamond within the big diamond.


The depth is the height of a diamond measured from the culet to the table.

Depth Percentage (%):

The depth percentage is the height of a diamond divided by the width. The depth percentage is used to measure whether or not a diamond is cut in the right proportions.

Emerald Cut:

An emerald cut diamond has a more glass-like appearance since its facets usually span the length or width of the diamond. An Emerald cut is also called a Step cut, usually a rectangular cut with cropped corners. The Emerald cut has an elegant and sophisticated look because of its trim lines.


The facet is the smooth plane of a diamond. Brilliant cuts have 57 or 58 triangular facets that makes them "sparkle," whereas emerald cuts have fewer facets and have a more glass-like look.

Fancy Color:

By unusual accidents of nature, diamonds also occur in shades of pink, blue, green, amber and red. These atypical colors are called Fancy Colors. Fancy Colors are evaluated by a different set of color standards. These standards take into account different factors such as shade, tinge and saturation. Because they are extremely scarce, Fancy Color diamonds are the most expensive.

Feathers (Glets):

Feathers or Glets are cracks inside a diamond that are perpendicular to the crack plane. They have an appearance quite similar to broken glass. Small internal feathers diminish the clarity rating of a diamond. Other than that they are undisruptive. Large feathers, on the other hand, pose a greater problem because the crack might expand as the diamond ages.


When light is refracted within the diamond, the result is multi-colored light beams emanating from the table. This phenomenon is called fire due to the resemblance to actual fire. A well-proportioned diamond will have a better fire effect.


Fluorescence refers to the ability of a diamond to fluoresce under ultraviolet (UV) light. The sun emits some UV light but it is usually insufficient to detect fluorescence. The most common source of UV is a black light. Most diamonds will give off a distinctive glowing blue coloration when exposed to UV light. Although fluorescence may be present in various colors, blue is the most common in diamonds. The fluorescence of a diamond is defined by its intensity as either None, Faint, Medium, Strong, or Very Strong. Typically, diamonds with a strong or very strong fluorescence are less expensive than other diamonds with weaker fluorescence.


The girdle is the narrow band around the width of the diamond where the crown and the pavilion meet. It is the outer edge of a diamond and it usually has a frosted appearance. Some diamonds have a fully polished or even a faceted girdle. This characteristic does not affect the value of the diamond and it is often more a reflection of the proclivity of the diamond cutter. The girdle is rated in terms of thickness. The size of the girdle may be: Extremely Thin, Very Thin, Thin, Medium, Slightly Thick, Thick, Very Thick, or Extremely Thick.


Inclusions are internal features that are wholly or partially enclosed by the diamond. There are several types of inclusions, such as crystalline and solid inclusions, dot-like inclusions, clouds, cracks (cleavage crack, fracture crack, tension crack) and structural phenomena. Inclusions are either visible to the unaided human eye (usually SI-3 clarity and below) or detectable only under a 10-power magnification. The rarity of a diamond is determined by the number of inclusions. That is to say, that fewer inclusions denote a better clarity grade, thus a higher value for the diamond.

Lab Certificate:

The proper quality of a diamond is imperative for determining its value. A diamond incorrectly graded by only the slightest margin could significantly affect its perceived value. There are several trustworthy independent grading laboratories. The most well-known laboratories are the Gemological Institute of America (GIA), the American Gemological Society Laboratory (AGSL), and the European Gemological Laboratory (EGL).
The American Gemological Society was established in 1934 by a select group of independent jewelers, including Robert M. Shipley, the founder of the prestigious school of gemology called the Gemological Institute of America (GIA). The vision of this group of jewelers was to establish an association dedicated to setting and upholding the highest standards of business ethics and professionalism in the jewelry industry. Nowadays, members of the AGS maintain their commitment to business ethics, knowledge and consumer protection.
The GIA is a non-profit organization whose functions include gemological education, research and certification. There are other well-known gemological laboratories such as the European Gemological Laboratories (EGL).
The scientific grading reports provided by these laboratories examine primarily the Four C's: Cut, Color, Clarity and Carat Weight, in addition to some other detailed specifications. These reports are recognized worldwide as the best professional opinions available.


The pavilion is the bottom portion of a diamond from the girdle (the thickest part around the stone) to the culet (the tip at the bottom).


The pinpoint is a very small dot - white or black - internal to a diamond or on the surface of the stone. It is the most common defect that can be found on or within a diamond.


A point is a weight measure that is equal to 1/100 carat. For instance, a 3/4-carat diamond is also a 75-point diamond.


As the name implies, the polish refers to the finishing or final buffing of the facets or flat surfaces of the diamond. Contrary to widespread belief, diamonds are ground and polished, not chipped away, until they reach their final form. An expert diamond cutter will carefully fashion each facet, so that it will shine without any polishing imperfections. The categories used in order to refer to the polish of a diamond are: Poor, Fair, Good, Very Good, Excellent, and Ideal. When purchasing a diamond, one should select a polishing grade of Good at the very least.


The form to which a diamond is cut is called the shape of a diamond. There are primarily 10 diamond shapes to choose from, including round, princess, emerald, Asscher, cushion, radiant, pear, oval, marquise, and heart.


The symmetry attribute of a diamond is used in order to describe the alignment and positioning of the facets or flat surfaces. The diamond cutter will carefully and cautiously position each facet in accurate proportion and relationship to the other facets. The alignment of each facet should be extremely precise because improperly joined facet junctions can make a diamond appear uneven.
To define the symmetry of a diamond, the commonly used terms are: Excellent, Very Good, Good, Fair, and Poor. When purchasing a diamond, one should select a symmetry grade of Good at the very least.


The table is the largest surface on a diamond. It is the top portion of the diamond, i.e., the portion that usually faces the viewer. The crown of the diamond culminates in the table.

Table Percentage (%):

The table percentage is equal to the width of the table divided by the diameter of the diamond. The table percentage is used in order to measure the accuracy and the proportions in which a diamond is cut. This is crucial to the "sparkle" of a diamond.

Diamond Shapes:

Found in nature as raw material, diamonds are subsequently cut in different shapes. Diamond shoppers often confuse the shape of a diamond with its cut. The shape is the basic form of the diamond, e.g., oval-shaped, pear-shaped and so forth. The cut or proportions of a diamond, on the other hand, determines the ability of each particular shape to reflect light.
For example, a diamond may be both beautifully round shaped but poorly cut (determined by its proportions), thus reflecting light inadequately. Therefore, Amberley West strongly recommends buying the best cut that you can afford.
The shape of a diamond is simply a matter of personal fondness. Naturally, different people prefer different shapes. Like many other fashion items, the shape of one's diamond is a statement of individuality and uniqueness.

Round Brilliant:

Round Diamond Shape Top ViewRound Diamond Shape Top ViewRound Diamond Shape Side ViewRound Diamond Shape Side View
The 'round brilliant' shape is the modern version of the 'round' shape, which has been refined for maximum shine. The 'round brilliant' is the most fashionable shape and it has the best angles, which makes it shine with maximum fire and brilliance.


Oval Diamond Shape Top ViewOval Diamond Shape Top ViewOval Diamond Shape Side ViewOval Diamond Shape Side View
The 'oval' shape is a symmetrical and elongated shape with an elliptical girdle that displays a brilliance similar to the 'round brilliant' shape. The 'oval' shape is very popular for three stones anniversary rings, with two matching diamonds on the sides. The 'oval' shape is particularly fashionable among women who have small hands or short fingers. Such women find that the 'oval' elongated shape creates a flattering illusion of length to a small hand.


Princess Diamond Shape Top ViewPrincess Diamond Shape Top ViewPrincess Diamond Shape Side ViewPrincess Diamond Shape Side View
A 'princess' shape is a square or rectangular modified brilliant cut diamond that has refractive properties that are relatively similar to the 'round brilliant' shape. The 'princess' shape is the preferred square cut shape.


Emerald Diamond Shape Top ViewEmerald Diamond Shape Top ViewEmerald Diamond Shape Side ViewEmerald Diamond Shape Side View
The 'emerald' is a rectangular shape with cut corners and is considered a more traditional shape. It has an ancient elegance associated with it.


Radiant Diamond Shape Top ViewRadiant Diamond Shape Top ViewRadiant Diamond Shape Side ViewRadiant Diamond Shape Side View
The 'radiant' shape has a square or rectangular cut. This shape combines the elegance of the 'emerald' shape with the brilliance of the 'round' shape. The 'radiant' shape is also known as a cut-cornered rectangular (or square) modified brilliant. The 'radiant' shape was popular before the 'princess' shape became more prominent. The 'radiant' shape has more facets than the 'princess' shape. The corners of the 'radiant' shape are trimmed like the 'emerald' shape. A 'radiant' shape diamond with a depth percentage of 70% to 78% is very common. The unique design of a 'radiant' shape diamond requires more weight toward the depth of the diamond while maximizing the brilliance of the diamond significantly.


Heart Diamond Shape Top ViewHeart Diamond Shape Top ViewHeart Diamond Shape Side ViewHeart Diamond Shape Side View
The 'heart' shape is rather difficult to find due to low demand but some people prefer a 'heart' shape diamond for sentimental reasons. The 'heart' shape diamond is considered to be the quintessential symbol of romance.


Marquise Diamond Shape Top ViewMarquise Diamond Shape Top ViewMarquise Diamond Shape Side ViewMarquise Diamond Shape Side View
The 'marquise' shape is an elongated shape with pointed ends. The 'marquise' shape, like the 'emerald' shape, is considered a traditional shape. Aside from the 'round brilliant,' the 'princess,' and the 'oval,' the 'marquise' is probably the most popular shape.


Pear Diamond Shape Top ViewPear Diamond Shape Top ViewPear Diamond Shape Side ViewPear Diamond Shape Side View
The 'pear' shape is a combination of the 'oval' shape and the 'marquise' shape. The 'pear' shape is generally used in pendants and earrings. A pear-shaped diamond is similar in appearance to a tear drop, and thus it has the right proportions for refracting light well.


Cushion Diamond Shape Top ViewCusion Diamond Shape Top ViewCusion Diamond Shape Side ViewCusion Diamond Shape Side View
The 'cushion' is a rectangular or square shape with rounded corners and a facet plan that gives the diamond depth. The 'cushion' shape is also called a "pillow cut." This shape has a 58-facet cut that is divided between its crowns (the top), girdle (the widest part) and pavilion (the base). It is then calibrated by means of an exact formula in order to accomplish the greatest degree of fire and brilliance.