Diamond Education


When shopping for a diamond, it is important to know how they are evaluated. Our comprehensive guide helps you understand the most important characteristics-carat, color, clarity, cut, and more-to ensure the maximum quality and value of your selection.

Diamond Shape

When selecting a diamond, shape is one of the most important factors to consider. The contours and outlines of a diamond have a significant impact on its appearance. The Goldery by Eternity Diamonds round cut diamond has long been the most popular, although many modern consumers prefer alternative shapes, including cushion, princess, and radiant, among others.

Round Diamonds

The most commonly chosen shape, round diamonds have been researched by gemologists more than any other variation. Renowned for its unrivaled fire and brilliance, this shape boasts excellent light refraction properties. When all else is equal, round cut diamonds are more valuable than alternative shapes.

Princess Diamonds

A square stone with 90-degree corners, the princess shape originated in the United States in 1980. The most desirable princess diamonds are perfectly square in shape, with the more rectangular variations decreasing in value.

Asscher Diamonds

Introduced in 1902 by renowned diamond cutter Joseph Asscher, this diamond shape utilizes many of the same cutting techniques as the emerald cut. What sets asscher diamonds apart are their uniquely angled and cropped corners creating a timeless look.

Radiant Diamonds

Relatively new to the jewelry industry, radiant diamonds were introduced a little more than 20 years ago. This unique shape is a stunning hybrid of a traditional round cut and an elegant emerald cut, resulting in a square, near-square, or rectangular orientation. As the name suggests, radiant diamonds tend to emit a beautiful, memorable glow.

Cushion Diamonds

First introduced to the jewelry market in the early 1800’s, the cushion cut diamond is rich with diamond history. Cut into a square or rectangular shape with rounded corners and sides, it's considered by many to be a more vintage version of the round cut diamond.

Emerald Diamonds

Emerald cut diamonds are usually rectangular in shape. Distinguished by beveled corners and step facets, this type of diamond is more transparent than other shapes, often requiring higher standards of clarity.

Marquise Diamonds

The marquise cut is rumored to have been specially developed for King Louis XIV of France who wanted a diamond that simulated the smile of Marquise de Pompadour. The elongated Marquise stone has gracefully pointed ends for a dramatically beautiful appeal.

Oval Diamonds

Cut with the same number of facets as a round diamond, an oval shape emits nearly the same level of brilliance and fire. Due to its elongated shape, the oval cut can appear larger than a round diamond of equal carat (weight).

Pear Diamonds

Exuding elegance, the pear shape diamond (also referred to as a drop cut or teardrop diamond) is cut to resemble a drop of water with a single point and rounded end. The result is a cross between a round and marquise cut.

Heart Diamonds

Living up to its name, the heart cut diamond has become synonymous with love and affection, making it an excellent choice for an anniversary or engagement ring. One of the most demanding diamond cuts to create, a heart shaped stone requires great skill and dexterity from the diamond cutter.

Diamond Clarity

Inclusions found on a diamond can be considered nature's birthmarks, the distinguishing characteristics that make the stone unique. When grading a diamond, the amount of inclusions and blemishes has a direct impact on its clarity and value. Flawless diamonds containing no inclusions are extremely rare and very expensive. A majority of the commercially sold diamonds contains inclusions that are undetectable to the unaided eye.

To ensure a large selection, Eternity Diamonds offers diamonds with a range of clarity ratings from FL (Flawless) to I1 (Included). Diamonds with clarity ratings of I1 or higher contain inclusions that are typically undetectable without special magnified viewers.

Clarity Scale

A diamond's clarity rating is based on the size, number, and location of internal and external characteristics. Known as inclusions, internal characteristics include crystals, clouds, and feathers. External characteristics, or surface irregularities, are called blemishes. As most inclusions can't be seen by the naked eye, gemologists use a ten-power (10x) microscope to rate a diamond's clarity.

Flawless, Internally Flawless (FL & IF)

Contains no internal inclusions when viewed with 10x magnification. Internally Flawless diamonds may contain external characteristics (also known as blemishes).

Very Very Slightly Included (VVS1 & VVS2)

Contains minute inclusions that are extremely difficult to locate under 10x magnification.

Very Slightly Included (VS1 & VS2)

Contains minute inclusions, such as clouds, crystals, or feathers, which are difficult to locate with 10x magnification.

Slightly Included (SI1, SI2, & SI3)

Contains noticeable inclusions under 10x magnification, including clouds, knots, crystals, cavities, and feathers.

Included (I1, I2, I3)

Contains very obvious inclusions that can usually be seen with the naked eye, as well as under 10x magnification. Included diamonds sometimes display poor transparency and lack of brilliance.


Selecting a Clarity Grade

Below are some points to consider when selecting your desired clarity rating:

  • Those who prefer a diamond with little or no inclusions will likely choose a clarity rating of FL-IF or VVS. Although they are priced higher, these high-quality diamonds boast a near-perfect appearance.
  • While still considered high quality, diamonds rated in the VS clarity range will not cost as much as more premium clarities. VS diamonds will contain inclusions that are undetectable to the unaided eye
  • Considered by many to be a great value, SI1-SI2 diamonds will contain inclusions that can be detected with magnification, yet are typically undetectable to the unaided eye and do not detract from the beauty of the diamond. If you are considering a diamond with an SI rating, contact an Eternity Diamonds diamond and jewellery expert to ensure the inclusions are not visible to the naked eye.
  • Those who desire large carat weights at lower prices may choose diamonds in the SI3-I1 clarity range. Inclusions in these stones are usually noticeable without magnification.
  • The location of a diamond's inclusions significantly impacts the stone's clarity rating. External and internal characteristics hidden near the side facets of a diamond detract from its beauty less than inclusions and blemishes located in the center of the diamond.

Diamond Color

A diamond's colour has a significant impact on its appearance. With its many prismatic facets, a colourless diamond reflects light into a spectrum of hues, a characteristic often referred to as "fire". The presence of noticeable colour in a diamond may reduce its ability to reflect light. Consequently, diamonds with lower colour grades will not show the same luminosity and fire as those with higher grades. The most valuable diamonds have little to no detectable colour.

At Eternity Diamonds, we offer a large assortment of high-quality diamonds in colour grades ranging from D (colourless) to M (faint yellow). A majority of our diamonds appear virtually colourless to the naked eye.

Colour Scale

The diamond colour scale begins at D (colourless) and ends at Z (light yellow). Diamond colour is often difficult to discern when a diamond is viewed face up. Therefore, gemologists typically evaluate diamonds facedown against a pure white surface, illuminated by carefully controlled lighting. The diamond is then compared to master stones of predetermined colour.

D (Colourless)

Highest-quality colour grade a diamond can receive. A D-colour diamond is extremely rare and emits unrivaled brilliance.

E (Colourless)

Contains very minute traces of colour. Also a rarity, an E-colour rated diamond emits a high level of brilliance and sparkle.

F (Colourless)

Minute traces of colour can only be detected by a trained gemologist. This is a high-quality colour grade.

G,H (Near Colourless)

Contains noticeable colour only when compared to higher colour grades. Appearing colourless to the untrained eye, a G or H colour diamond provides an excellent value.

I,J (Near Colourless)

Contains slightly detectable colour. An I-colour or J-colour diamond is an excellent value, as it typically appears colourless to the untrained eye.


Selecting a Colour Grade

Colour is an important factor to consider when choosing a diamond, as it is noticeable to the unaided eye. Below are some points to keep in mind when selecting a colour grade:

Those who prefer a colourless diamond should select a stone in the D-F range with a fluorescence rating of "None" or "Faint".

Near colourless diamonds with a rating between G and J are excellent values, as their colour is typically undetectable to the unaided eye. If you are considering a diamond in this colour range, an Eternity Diamonds and jewellery expert can review the stone to ensure the colour cannot be seen with the naked eye.

A near colourless diamond can appear whiter when set in platinum or white gold metals. Yellow gold settings complement diamonds with lower colour ratings.

The presence of fluorescence can enhance the visual appeal of a diamond with a lower-colour rating in the J through M range. The fluorescence helps to cancel out any faint yellow in the stone, resulting in a colourless appearance.

A common misconception is that only colourless diamonds exude brilliance. In reality, a well-cut diamond can emit fire and beauty even with traces of faint yellow, although the presence of colour will decrease the stone's value.



Fluorescence, the effect ultraviolet (UV) light has on a diamond, is an important consideration when selecting a diamond. When UV light strikes a diamond with fluorescent properties, the stone emits a glow (usually blue) ranging from very faint to quite strong.


Fancy Coloured Diamonds

Diamonds that exhibit a colour other than light yellow or brown, as well as diamonds that possess a more intense yellow or brown than the 'Z' colour rating, are considered "fancy coloured". With only one out of ten thousand diamonds possessing a natural colour, these types of stones are extremely rare. Depending on the colouration, intensity, and hue of a diamond, colour can either detract or enhance its value. Naturally occurring diamond colours include gray, white, blue, yellow, orange, red, green, olive, pink, purple, brown, and black. Red stones are the most rare of the fancy coloured diamonds.

Similar to the process for grading colourless diamonds, a diamond's fancy colour is graded by comparing it to master stones of predetermined colour. Unlike colourless diamonds, fancy coloured diamonds are graded face up. The most important factors in determining the value of a naturally coloured diamond is the strength of its colour. The value of a fancy coloured diamond increases with the intensity of the most prominent hue within the stone.

Diamond Carat

The carat is the standard unit of measurement used to indicate the weight of diamonds and precious gemstones. Since 1913, carat weight has been gauged against the metric system, with one carat equaling 0.2 grams or 0.007 ounces. Carat weight is measured to three decimal points and rounded to the nearest hundredth.

Carat Weight and Price

Mined from deep within the layers of the Earth's crust, most rough diamonds are either too small or too inferior in quality to produce the lustrous, polished products demanded in the fine jewellery market. Consequently, the production of a single, one-carat diamond can require the mining of up to one million rough diamonds. The rarity of larger, high-quality diamonds has resulted in significant price escalations between sizes. For instance, a one-carat diamond can command four to six times more than a half-carat diamond.

Selecting a Carat Weight

Both carat size and quality should be taken into account when selecting a diamond. Below are some points to consider when choosing which carat weight is right for you:

  • Diamond pricing is determined by carat weight, and broken down in half-carat increments. Therefore, assuming factors like cut and clarity are equal, a diamond weighing one carat will cost more than a diamond weighing slightly less than one carat.
  • While its carat measurement indicates the weight of a diamond, its length and width measurements indicate the actual physical size, or how big the diamond will appear when viewed from above. Diamonds of the same carat weight can vary in size. For example, a one-carat round diamond could measure 5.9 mm in diameter, while another one-carat round diamond could be 6.5 mm wide. Broader diamonds with larger millimeter measurements create greater visual impact.
  • The price of a diamond rises as the carat weight increases. If carat weight is the most important factor in your search, consider a diamond with a clarity grade of Slightly Included (SI1-SI3) and a colour grade of Near Colourless (G-J).
  • The shape of a diamond may impact how the stone appears when viewed from above. Diamond shapes cut at lower depths will have larger lengths and widths. Shapes like oval or marquise will have elongated lengths, resulting in the illusion of a larger size per carat weight.
  • When choosing a carat weight, be sure to consider the ring size of the wearer. A one-carat diamond will appear larger on a size-5 finger than it would on a larger hand.
  • If you have already chosen a ring setting or have one in mind, you may be restricted to certain diamond shapes and carat ranges.

Carat Origin

The origin of the word -carat- lies in the Mediterranean region, where carob trees have flourished since ancient times. The seeds of the carob tree were once used as units of measurement against which diamonds were weighed. One carob seed is roughly equivalent to one modern carat, the word we use today to describe the weight of diamonds.

In the Far East, diamonds were historically weighed against grains of rice, resulting in the coining of the term 'grainer'. Today, gemologists still quantify the weight of diamonds in grainers. A four-grainer diamond is equal to one carat.

Diamond Cut

One of the most defining characteristics of a diamond is its cut. While high grades of color, clarity, and carat weight also contribute to a diamond's appeal, it's the cut that determines the symmetry of the stone's facets, its overall proportions, and its ability to reflect light. An expertly cut diamond will achieve high levels of brilliance, sparkle, and durability. Even if a diamond is graded well in other areas, a poor cut can result in a dull, muted effect.

Diamond Fluorescence

Fluorescence, the effect ultraviolet (UV) light has on a diamond, is an important consideration when selecting a diamond. When UV light strikes a diamond with fluorescent properties, the stone emits a glow that is usually blue, but can also be shades of green, yellow, white, pink, orange, and red. The sources of fluorescence, boron and nitrogen, are the same mineral properties that lend to diamond coluor.

Fluorescence can occur in different intensities. Gemological laboratories rate the fluorescence of each diamond on a scale from "None" to "Very Strong".

Diamond Girdle

The girdle is the thin perimeter of a diamond, dividing the crown above from the pavilion below. When viewing a diamond in its setting or from a profile view, the girdle is the widest part (or the circumference) of the polished diamond - the portion of the stone that makes contact with the setting itself. When loose diamonds are measured, they are measured by the girdle to obtain length and width in millimeters.

The girdle of a diamond can be rough, polished, or faceted. In modern gemstone preparations, brilliant cut diamonds (with triangular-shaped facets) usually have a faceted girdle rather than a perfectly round girdle; this gives the gem a higher measure of transparency. Step cut diamonds (with rows of elongated facets that act as mirrors) usually have polished girdles that are not faceted.

Diamond Culet

The culet (pronounced kyoo-lit) of a diamond is the tiny point at the base of the pavilion, where the facets of the pavilion meet. In the majority of diamonds, the pavilion facets are uniformly cut at the proper angle and meet at a perfect point, yielding no culet (sometimes called a pointed culet). When the pavilion facets do not meet at a point, the culet is a rough or polished facet. The presence of a culet adds an additional facet to the diamond's total number of facets, while a pointed culet does not. For example, a brilliant round diamond with a faceted culet has 58 facets, while a diamond with a pointed culet has 57 facets.

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