Diamond Education

What is Diamond?

Diamonds were formed billions of years ago under intense heat and pressure when diamond-bearing ore was brought to the surface through volcanic eruption. After the magma cooled, it solidified into blue ground, or kimberlite, where precious rough diamonds are still found today.

Diamond is an allotrope of carbon where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material.

The formation of natural diamond requires very specific conditions—exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilo bars (4.5 and 6 GPa), but at a comparatively low temperature range between approximately 900–1300 °C (1652–2372 °F). These conditions are met in two places on Earth; in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike. Most natural diamonds are formed at high temperature and pressure at depths of 140 to 190 kilometers (87 to 120 miles) in the Earth's mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years.

Shapes

The classic diamond is, to most people, a round gem of sparkling white brilliance with a kaleidoscope of dazzling facets to entice the eye. Yes and no. Diamonds are natural crystals of varying size and shape formed in the earth over millions of years. The traditional round brilliant diamond, though the most popular diamond shape of all, is hardly the whole story. By the diamond cutter's art these crystals are carved into gems of spectacular and whimsical beauty. A cutter's skill will produce a diamond of the greatest size with the fewest flaws and the most brilliance.

Round Brilliant Diamonds

This shape has set the standard for all other diamond shapes, and accounts for more than 75% of diamonds sold today. Its 58-facet cut, divided among its crown (top), girdle (widest part) and pavilion (base), is calibrated through a precise formula to achieve the maximum in fire and brilliance. Developed ca. 1900, the round brilliant is the most popular cut given to diamond. It is usually the best choice in terms of saleability, insurability (due to its relatively "safe" shape), and desired optics.

The modern round brilliant (Figure 1 and 2) consists of 58 facets (or 57 if the culet is excluded); 33 on the crown (the top half above the middle or girdle of the stone) and 25 on the pavilion (the lower half below the girdle). The girdle may be frosted, polished smooth, or faceted. In recent decades, most girdles are faceted; many have 32, 64, 80, or 96 facets; these facets are excluded from the total facet count. Likewise, some diamonds may have small extra facets on the crown or pavilion that were created to remove surface imperfections during the diamond cutting process. Depending on their size and location, they may hurt the symmetry of the cut and are therefore considered during cut grading. Figure 1 assumes that the "thick part of the girdle" is the same thickness at all 16 "thick parts". It does not consider the effects of indexed upper girdle facets. Figure 2 is adapted from the Tolko sky book, which was originally published in 1919. Since 1919, the lower girdle facets have become longer. As a result, the pavilion main facets have become narrower.

Oval Diamonds

An even, perfectly symmetrical design popular among women with small hands or short fingers. Its elongated shape gives a flattering illusion of length to the hand. The Oval Diamond has beautiful brilliance that's similar to a round diamond. Oval diamonds are also very popular as their length can accentuate long, slender fingers.

The history of the brilliant-cut oval diamond is relatively easy to track because it is a relatively young shape. Created by Lazare Kaplan in the late 1950s -early 1960s, the oval brilliant cut is an elipitical variation of the more common round brilliant. The modern oval cut is a fiery diamond that reflects light brilliantly. It's a wonderful selection for someone who loves the sparkle of the round brilliant, but desires a less common shape.

Marquise Diamonds

An elongated shape with pointed ends inspired by the fetching smile of the Marquise de Pompadour and commissioned by the Sun King, France's Louis XIV, who wanted a diamond to match it. It is gorgeous when used as a solitaire or when enhanced by smaller diamonds.

Pear Shaped Diamonds

A hybrid cut, combining the best of the oval and the marquise, it is shaped most like a sparkling teardrop. It also belongs to that category of diamond whose design most complements a hand with small or average-length fingers. It is particularly beautiful for pendants or earrings.

The pear shaped diamond is also called the "teardrop diamond" because of its shape. The pear shaped diamond is a combination cut of the round-brilliant and the marquise (to see examples of these two shapes, visit our diamond shapes page.

The Pear Shaped Diamond is a fiery cut with lots of wonderful sparkle and flash. The elegant lines of the Pear Shaped Diamond lends a sophisticated air to both the simplest and most elaborate ring settings.

Heart Shaped Diamonds

This ultimate symbol of romance is essentially a pear-shaped diamond with a cleft at the top. The skill of the cutter determines the beauty of the cut. Look for a stone with an even shape and a well-defined outline.

Though a technical description of the heart-shaped diamond is anything but sentimental, (the heart shaped diamond is essentially a pear-shaped diamond with a cleft at the top), the diamond itself is considered by some to be the most romantic of all diamond cuts.

The heart shaped diamond can be quite fiery with excellent sparkle.

Emerald Cut Diamond

This is a rectangular shape with cut corners. It is known as a step cut because its concentric broad, flat planes resemble stair steps. Since inclusions and inferior color are more pronounced in this particular cut, take pains to select a stone of superior clarity and color. As may be evident by the name, the "emerald cut" was originally developed for cutting emeralds, not diamonds.

While the emerald gemstone is a relatively hard stone (7.5 - 8.0 on the MOHS scale), it is known for numerous inclusions (naturally occurring internal flaws). The inclusions make the stone vulnerable to breakage, making them difficult to cut. The stepped, normally rectangular cut with cropped corners (shown above), known as the "emerald cut" was developed to address these issues.

It was soon discovered that the emerald cut was also suitable for other stones, including diamonds.

The emerald cut diamond can be absolutely stunning. Because of it's long lines, it tends to be less fiery than a "round brilliant" cut, but it also tends to have broader, more dramatic flashes of light. The trim lines of emerald cut diamonds lend an elegant, sophisticated air to both the simplest and most elaborate ring settings.

Princess Cut Diamond

This is a square or rectangular cut with numerous sparkling facets. It is a relatively new cut and often finds its way into solitaire engagement rings. Flattering to a hand with long fingers, it is often embellished with triangular stones at its sides. Because of its design, this cut requires more weight to be directed toward the diamond's depth in order to maximize brilliance. Depth percentages of 70% to 78% are not uncommon.

If you love the fire of the traditional Round Brilliant Cut (the standard diamond engagement ring cut), but want something a little different, you might just fall in love with the icy fire of the square Princess Cut Diamond.

Most square or rectangular cuts just don't live up to the round brilliant for sparkle, but the Princess Cut was designed for getting maximum brilliance from a square cut.

Always ensure that the setting for your princess cut diamond protects the four pointed corners -- these are the points most likely to chip (and why most rectangular or square diamond cuts have cropped corners).

Radiant Cut Diamonds

This square or rectangular cut combines the elegance of the emerald shape diamond with the brilliance of the round, and its 70 facets maximize the effect of its color refraction. Because of its design, this cut requires more weight to be directed toward the diamond's depth in order to maximize brilliance. Depth percentages of 70% to 78% are not uncommon.

If you love the fire of the traditional Round Brilliant Cut (the standard diamond engagement ring cut) and the shape of the less fiery Emerald Cut and Asscher Cut, you just may love the Radiant Cut Diamond.

Most square or rectangular cuts just don't live up to the round brilliant for sparkle, but the Radiant Cut was designed for getting maximum brilliance. Like the emerald cut, the radiant cut diamond is often a rectangle (sometimes square) with cropped corners, but that's where the similarities end. Where the emerald cut has long trim lines, the radiant cut is faceted for fire.

Trilliant Diamonds

This is a spectacular wedge of brittle fire. First developed in Amsterdam, the exact design can vary depending on a particular diamond's natural characteristics and the cutter's personal preferences. It may be a traditional triangular shape with pointed corners or a more rounded triangular shape with 25 facets on the crown, 19 facets on the pavilion, and a polished girdle. It is definitely for the adventurous.

Cushion Cut Diamond

An antique style of cut that looks like a cross between an Old Mine Cut (a deep cut with large facets that was common in the late 19th and the early 20th centuries) and a modern oval cut.

Until recently, it was difficult to find Cushion Cut Diamonds for sale outside of estate sales and auctions. However, cushion cuts are enjoying a small surge in popularity.

The cushion cut is an antique cut that most often resembles a cross between the Old Mine Cut (a deep cut with large facets that was common in the late 19th and the early 20th centuries) and a modern oval cut. This shape is also sometimes referred to as the pillow-cut or the candlelight diamond (a reference to cuts designed prior to electric lights, when diamonds sparkled in the light provided by candles).

This cut is not as fiery or brilliant as many of the newer cuts, but it has a marvelously romantic and classic look and definitely stands out from the crowd of round brilliants.

The shape of things to come in diamonds has already produced other fanciful and innovative styles such as the flower, cloverleaf, triangle and kite. Nor does it stop there. Some cuts are variations on standard shapes, others spin off the natural crystal formation of the stone, and still others take the idea of shape to revolutionary new heights. Individuality and taste determine the fashion, and the magic of the gem cutter transforms each stone into a unique work of art.

Carat

Carat is the unit of measurement used to describe the weight of diamonds. One carat is equal to 0.2 grams, or 0.007 ounces (avoirdupois). Five carats equals 1 gram, and 141.7 carats equals 1 ounce.

Carat weight is commonly expressed in points or fractions. There are 100 points in 1 carat. For instance, 0.33 carats is generally expressed as 33 points, or 1/3 of a carat.

Why is carat weight important?

The carat weight of a diamond is a major factor in its price, but the cut, color, and clarity will also affect the price greatly. A 0.50-carat diamond with high color and clarity ratings may cost more than a 0.75-carat diamond with lower color and clarity ratings.

Within a specific price range, you will find a number of combinations of diamond carat weight and quality. If you value size over quality, you might choose a 1.00-carat diamond with an I or J color and SI2 clarity with a Good cut to get maximum size. For the same price, if you value quality over size, you might choose a 0.75-carat diamond with an E or F color and VS2 clarity with an Ideal cut.

Because large diamonds are much rarer in nature than small ones, diamond value increases exponentially for certain thresholds of diamond carat weights. A 1.00-carat diamond will cost more than twice as much as a 0.50-carat diamond of comparable quality.

does carat weight affect diamond size?

As diamond carat size increases, both the diameter and the depth of the diamond increase. This is why a 1.00-carat diamond (approximate 6.5mm diameter) does not look twice as wide as a 0.50-carat diamond (approximate 5mm diameter).

When choosing a diamond size, keep the size of the wearer in mind. A 1.00-carat solitaire will appear much larger on a size 4 finger on than a size 8.

does carat weight affect diamond size?

As diamond carat size increases, both the diameter and the depth of the diamond increase. This is why a 1.00-carat diamond (approximate 6.5mm diameter) does not look twice as wide as a 0.50-carat diamond (approximate 5mm diameter).

When choosing a diamond size, keep the size of the wearer in mind. A 1.00-carat solitaire will appear much larger on a size 4 finger on than a size 8.

does carat weight affect diamond size?

Minimum individual carat weight is the minimum carat weight of one diamond in a piece of jewelry. If a pair of diamond stud earrings has a total diamond weight of 1/2 carat, the individual carat weight of each diamond would be 1/4 carat. The actual diamonds you purchase may weigh slightly more or less than the fractional weight specified. The Federal Trade Commission has strict guidelines about the disclosure of the range of carat weight that a fraction can represent. The chart below outlines acceptable ranges for carat weights expressed as fractions. Some diamonds may be cut into sizes between these more common fractions. Because it is more unusual for diamonds to be cut into these in-between sizes, ranges are not defined for these sizes. These sizes would have their specific carat weight (e.g., 0.62 carats) listed under minimum individual carat weight.

  • 1/4 carat total weight may be 0.21 to 0.29 carats
  • 1/3 carat total weight may be 0.30 to 0.36 carats
  • 1/2 carat total weight may be 0.45 to 0.59 carats
  • 3/4 carat total weight may be 0.70 to 0.84 carats
  • 1 carat total weight may be 0.95 to 1.10 carats
  • 1 1/4 carats total weight may be 1.20 to 1.29 carats
  • 1 1/2 carats total weight may be 1.45 to 1.55 carats
  • 2 carats total weight may be 1.95 to 2.05 carats

Color

Diamonds are found in almost every color of the rainbow, but "white" (colorless) diamonds remain most popular.

The finest and most expensive diamonds are totally without color, like a drop of distilled water. The rainbow hues a diamond flashes derive from the light it separates into the colors of a spectrum. Diamonds of lesser quality have a yellowish or brownish cast.

When describing the colour of a diamond reference is being made to the degree of colour found in that diamond. The less colour displayed in a diamond the better the colour grade.

Diamonds can be found in almost every colour of the rainbow, colourless diamonds remain the most popular. When describing the colour of a diamond reference is being made to the degree of colour found in that diamond. The less colour displayed in a diamond the better the colour grade. Diamonds displaying little colour will allow more light to pass though, creating a prism effect , with its spectrum of colours and flash , known as fire. The Gemological Institute of America (GIA) rates the body color in white diamonds from D (colorless) to Z (light yellow). Increasing degrees of body colour are measured on a scale ranging from no colour at all (D) to deeply coloured (Z). Beyond "Z" is the range where the diamond's colour is vivid and rich, called "fancy colours". Diamonds of known colour are used as comparison stones for colour grading. Grading is done by comparing the diamond to be graded against these "master stones" under either artificial or natural north daylight (in the Northern Hemisphere). A machine called the "Colorimeter" can be used for colour grading but there is no substitute for the trained human eye.

Clarity

Every diamond is unique. Nature ensures that each diamond is as individual as the person who wears it. Diamond clarity is a quality of diamonds relating to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects called blemishes. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. A clarity grade is assigned based on the overall appearance of the stone under ten times magnification.

Diamonds with higher clarity grades are more valued, with the exceedingly rare Flawless graded diamond fetching the highest price. Minor inclusions or blemishes are useful, as they can be used as unique identifying marks analogous to fingerprints.

The GIA diamond grading scale is divided into six categories and eleven grades. The clarity categories and grades are:

Cut

Nature determines so much about a diamond, but it takes a master cutter to reveal the stone's true brilliance, fire and ultimate beauty.

Based on scientific formulas, a well-cut diamond will internally reflect light from one mirror-like facet to another and disperse and reflect it through the top of the stone. This results in a display of brilliance and fire. Diamonds that are cut too deep or too shallow lose or leak light through the side or bottom, resulting in less brilliance and ultimately, value.

Of all the 4C's, cut is the only one most directly influenced by the human hand. The other three are dictated by nature.

Our most brilliant cut, representing roughly the top 1% of diamond quality based on cut. The highest grades of polish and symmetry allow it to reflect even more light than the standard ideal cut.

Ideal/Excellent cut: Represents roughly the top 3% of diamond quality based on cut. Reflects nearly all light that enters the diamond. An exquisite and rare cut

Very good cut: Represents roughly the top 15% of diamond quality based on cut. Reflects nearly as much light as the ideal cut, but for a lower price.

Good cut: Represents roughly the top 25% of diamond quality based on cut. Reflects most light that enters. Much less expensive than a very good cut.

Fair cut: Represents roughly the top 35% of diamond quality based on cut. Still a quality diamond, but a fair cut will not be as brilliant as a good cut.

Poor cut: Diamonds that are generally so deep and narrow or shallow and wide that they lose most of the light out the sides and bottom.

DIAMOND CUT PROPORTIONS

Diamond proportion refers to the relationship between the size, shape, and angle of each facet of a diamond. A wide range of combinations are possible, ultimately determining the diamond's interaction with light. When light strikes a diamond, approximately 20% immediately reflects off the surface (as glare). Of the 80% that enters, a portion will escape through the bottom of the diamond (where the observer cannot appreciate it). A well proportioned diamond will have each facet properly placed and angled so as to maximize the amount of light that reflects back out of the crown (top) of the diamond, to the eye of the observer. This reflected light is perceived as scintillation, fire and brilliance.

In the diagram below, three common light patterns are shown. When light meets any facet of a diamond, it will either reflect (bounce back) or refract (bend while passing through the facet). The angle that the light hits the facet determines whether the majority of light reflects or refracts, which is why cut is so important.

If the diamond cut is too shallow, entering light strikes the pavilion facet at a low angle and passes through the facet (refracts), escaping through the bottom of the diamond.

In a well (Ideal) cut diamond, the light strikes each pavilion facet at an angle which allows most of the light to reflect back to the crown (top). As it passes through the crown facets at a low angle, the light refracts upon exit. In this case, refraction is a good thing, as the bent light travels to the observer's eye and is perceived as a lively fire.

If the diamond cut is too deep, entering light strikes the first pavilion facet at an angle sharp enough to reflect to the second pavilion. But the light strikes the second pavilion at too low an angle, causing the light to refract (pass through the facet), escaping through the bottom of the diamond.

Diamond Polish

When diamond graders consider what Polish grade to assign, they consider the amount and visibility of any 'polish imperfections'. These may be things like pits, scratches, chips, polish lines or burn marks.

There are five GIA Polish categories: Poor, Fair, Good, Very Good and Excellent.

Very Good and Excellent polish in a diamond means that no polish features can be seen with the naked eye. Good polish means you still can't see any polish features with the naked eye, but they are there and the luster of the diamond may be slightly affected depending on the nature and size of the mark. A diamond with a Fair or Poor Polish grade may have surface marks that are noticeable with the naked eye and will have significantly affected luster.

Diamond Symmetry

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Poor, Fair, Very Good, Good, and Excellent: There are five categories of GIA Symmetry.

Very Good and Excellent symmetry graded diamonds have no or a very small symmetry under 10x magnification will be problems. A Good symmetry, note the symmetry is clearly visible under 10x magnification features.

Fair or Poor Diamonds significantly affected by symmetry, it is common to make the diamond sparkle and shine to lose is allowed to infiltrate.

Hearts and Arrows

A "Hearts & Arrows" cut diamond is the finest cut diamond. Extremely rare, its sentimental charm and mystery are unparalleled. The term Hearts and Arrows is used to describe the visual effect achieved in a round brilliant cut diamond with perfect symmetry and angles that exhibit a crisp and complete pattern of Hearts & Arrows. When viewed under a special magnifying viewer, a complete and precise visual pattern of 8 hearts is seen while looking down through the pavilion and 8 arrows can be seen when viewing the stone in the table up position

Fancy color Diamond

A "fancy colour diamond" is a natural coloured diamond, found in a wide range of hues, including red, green, purple, violet, orange blue and pink. These diamonds are amongst the most rare and beautiful diamonds that nature has to offer. In fact, out of the approximately 80 000 carats of rough diamonds mined every year, only 0.001% are regarded as fancy colours.

Fancy colored diamonds are known worldwide as extremely rare, and thus, are very popular with Hollywood movie stars.

In order to classify diamonds as NATURAL loose colored diamonds, they are certified in a gemological institute.

Once a stone has been graded and certified, the natural loose diamond will have its own personal ID which includes an ID number for the loose diamond, measurements of the loose diamond, weight, shape, clarity, polish, symmetry and fluorescence.

When it appears as a single color, the price of the diamond will be considerably more expensive than a diamond with a secondary hue - for example, fancy Brownish Greenish Yellow, fancy Orangey Pink, or fancy Grayish Blue.

The intensity grading system for fancy color diamonds differs than that of white diamonds. Unlike white diamonds, which range from the letter D-Z, fancy color diamonds are graded by Light, Fancy Light, Fancy, Fancy Intense, Fancy Deep , Fancy Dark, and Fancy Vivid. The stronger the color - the higher the price.

Red Diamonds


Red is by far the rarest of all coloured diamonds. Fewer than 20 stones have so far been certified as red diamonds. Some of these have fetched over a million dollars per carat, although most other coloured diamonds fetch between five to six figures per carat.

Pink Diamonds


Pink diamonds are rare and highly desired. Pink diamonds of higher intensity are the most rare and command very high prices. Most pink diamonds mined are faint to light coloured (pastel coloured). Many of the deep coloured pink diamonds come from the Argyle mine in Australia.

Yellow Diamonds


Yellow is one of the most familiar names known aside from white "colourless" diamonds. Canary is a term commonly used to describe intense yellow diamonds. Some of the yellows with higher intensity of colour (Fancy Vivid Yellow) are as rare as the pinks and blues and command unusually high prices.

Blue Diamonds


Natural blue colour is one of the rarest of fancy colour diamonds. These diamonds are amongst the most sought after by collectors. Colour can range from faint to a very deep blue, and blue diamond can command even higher prices than pink diamonds.

Green Diamonds


Green diamonds with no other secondary hues or modifiers are some of the rarest, and depending on intensity and purity of colour, can command astronomical prices. Most green diamonds have either grey, brown or yellow modifiers.

Orange Diamonds


Orange diamonds are not as rare as the red or green diamonds. Most orange coloured diamonds have strong yellow or brown modifiers. Pastels coloured orange diamonds are of similar values pastel pinks and some blues.

Purple Diamonds


Purple diamonds with no secondary hues are very rare. Most of these diamonds are less than one carat in size and are very seldom found in dark to vivid lilac colours. Most purple diamonds exhibit needle-like colour zones.

Brown Diamonds


These are the most widely available and surprisingly affordable coloured diamonds. They provide a beautiful low cost alternative to pink, blue, grey, green or yellow diamonds. Common names used to describe brown colour are: champagne, chocolate, coffee, golden, honey, bronze, cognac, etc.

Grey Diamonds


Diamonds with grey as the primary dominant colour are also unique. These diamonds are comparatively reasonably priced (in the high four to low fice figures per carat).

Black Diamonds


Black diamonds are not transparent, and do not shows fire (flashes of colour) as other diamonds, but can be extremely expensive where they are in the dark to vivid colour ranges. Black diamonds may give off secondary colour hues of grey or white.

How are fancy colors graded?

Fancy Color begins beyond the grade Z in the color grading scale. (shown above) While colorless, near colorless, faint and light diamond colors are graded from the face-down position. Laboratory graders assess fancy color diamonds from the face-up or top view of the diamond.

Graders evaluate the hue, tone, and saturation of each diamond.

Hue - A diamond's overall body color

Tone - A diamond's lightness or darkness in relation to body color

Saturation - The intensity or degree of color

Secondary or modifying colors are also assessed, as they impact the overall hue of the fancy color. For example, a yellow diamond may have a green secondary, and will subsequently be graded as "Fancy Greenish Yellow." A blue diamond may have a grey secondary color, and will be graded as "Fancy Greyish Blue" and so on.

Fancy diamond colours are also described by color “overtone” (modifying colour). Modifying color is always listed before the main color.

Intensity

The color in Fancy color diamonds is built from three parameters:

  • he main color of the diamond
  • he secondary color of the diamond (AKA overtone)
  • he intensity of the color

The main color, and if there is a secondary color, together define the color tone, however the strength of color is defined by the intensity level. The intensity level can be anywhere from a very soft shade to a very strong shade, and the stronger the shade the more valuable the diamond is. GIA developed an intensity grading scale in order to categorize the intensity levels in the diamond. The nine grades in the scale are;

  • Faint
  • Very Light
  • Light
  • Fancy Light
  • Fancy
  • Fancy Intence
  • Fancy Vivid, Fancy Deep, Fancy Dark

Fancy Intense – Fancy intense color diamonds exhibit a moderate tone, with a stronger saturation.

Fancy Vivid – Fancy vivid color diamonds are graded as having a moderate tone, with a strong saturation. These diamonds exhibit an intense, vibrant hue and are considered especially rare and valuable

For example, the following image depicts the full scale of color intensity in Pink, Blue, and Green color Diamonds. It is clearly shown that the intensity scale begins with very soft colors and progressively displays a richer color stone.

However, it is important to understand that not every diamond color appears in all intensity levels. For example, Orange diamonds cannot be found in Faint, Very Light, or Light intensities. Only Fancy Light, Fancy, Fancy Intense, Fancy Vivid, and Fancy Deep.

The GIA also defines how well the color and intensity is distributed throughout the stone. A diamond certificate will specify 'even' or 'uneven' according to the percentage of the color distribution.

The intensity of the color has a direct affect on the value of the stone. For example a Blue diamond or a Pink diamond, which are of the rarest in the fancy colored diamond family, are quite costly and difficult to find. However, there is a significant difference between a Fancy Light Blue and a Fancy Vivid Blue or a Fancy Light Pink and a Fancy Intense Pink.

Since there is such a wide range of colored diamonds, even stones of the same intensity can look quite different from one another. At Leibish & Co., the intensity of each diamond is graded on a scale of 1-10. The 1-10 scale breaks down different stones of the same intensity grade between a weaker or stronger color.

The following image saw the Fluorescence effect on Fancy Color diamond.

A ‘Fancy Intense Pink' diamond with a 1-3 grade is a very weak ‘Fancy Intense Pink’ and actually borders a ‘Fancy Pink.’ A ‘Fancy Intense Pink’ diamond with a 8-10 has a very strong color and actually borders a ‘Fancy Vivid Pink’ diamond. Therefore, it is actually quite common to see two diamonds of the same intensity grade where one looks as if the color is more intense than in the other.

The image about depicts four diamonds all graded by GIA as ‘Fancy Intense Pink’ with different strengths of the same intensity grade (and color tone) between the stones.

Exactly what color intensity a diamond will have will not be able to be determined from the rough stone. However, the greater the color intensity of the rough, the greater the intensity of the polished diamond will be. How intense the color will be is also greatly affected by the diamond cut and shape of the stone. Also, the way colorless stones are being cut (Brilliant cut) is different from how Fancy Color Diamonds are cut (Modified).

The origin of the diamond is also another factor that affects the color intensity. Different diamond mines produce different shades or tones of colors. For example, a Pink diamond found in India or South Africa can’t compare to a Pink diamond found from the Argyle diamond mine in Australia.

Fluorescence

Fluorescence is a characteristic that makes some diamonds appear to change color when they are exposed to the ultraviolet light that surrounds us every day in sunlight and in the light produced by fluorescent light bulbs.

Do All Diamonds Fluoresce?

Diamond grading reports reveal whether or not a diamond fluoresces, and if it does, how much -- faintly, weakly, moderately, strongly or very strongly.

What Color is Visible in Diamond Fluorescence?

Diamond grading reports also disclose the color produced by a diamond's fluorescence -- it's usually blue, yellow or white.

How Does Diamond Fluorescence Affect the Diamond

If a yellowish diamond fluoresces blue, the effect could be strong enough to mask the yellowish tint when viewed under a jewelry store's fluorescent bulbs. You might be surprised by the diamond's true (yellowish) color when you look at it at home under different lighting.

The reverse is true for diamonds that fluoresce yellow. They can appear more white under incandescent lights, but acquire a yellowish tint in ultraviolet light.

Is Diamond Fluorescence Bad?

Some retailers will tell you that fluorescence is bad...is a negative, but many consumers actually prefer diamonds with fluorescence! The truth is that fluorescence rarely affects a diamond's sparkle and brilliance, and in warmer or lower colored diamonds, fluorescence makes them look whiter or more colorless. Diamonds with fluorescence should be graded case by case. You may not even notice fluorescence in your diamonds, unless you are at a nightclub with black lights...Have fun and enjoy the blue glow!

About a third of diamonds exhibit fluorescence, like the fluorescent minerals you have seen in natural history museums or the novelty shop toys under the black (UV) light. The effect is like a white shirt in a discotheque. Fluorescence can be faint to very strong, and the most common fluorescent color is blue. As blue is the complimentary color to yellow, the most common tinted color in diamonds, blue fluorescence can make yellowish diamonds look white or colorless.

Fluorescence in Multi-Stone Rings

Most fluorescence is subtle. You probably will not see it as a true color change, just a slight shift in tone. However, the difference could make a diamond ring with multiple stones seem out of balance if some of the stones fluoresce and others do not, or if they fluoresce different colors.

Pricing for Diamonds that Fluoresce

A strong yellow fluorescence bring diamond prices down, sometimes quite a bit, since yellowish tinted diamonds are generally less desirable than whiter stones.

A blue fluorescence can help increase the prices of diamonds with yellowish tones.

It's important for you to be happy with the diamonds you buy. Ask your jeweler to show you examples of fluorescence and try to look at diamonds in many types of light before you make a decision, especially if you are considering diamonds with no grading documentation.

Certification

What are Certified Diamonds? Loose diamonds (not pre-set in a ring or other setting) that have been certified by Gemological Laboratory.

A certificate is a "blueprint" of a diamond, it tells you the diamond's exact measurements and weight, as well as the details of its cut and quality. It precisely points out all the individual characteristics of the stone. Certificates also serve as proof of the diamond's identity and value.

A certificate is not the same thing as an appraisal. A certificate describes the quality of a diamond, but it does not place a monetary value on the gem. An appraisal places a monetary value on your diamond, but does not certify the quality of the diamond.

Who Issues Certificates?

There are many diamond labs that issue certificates, but the Gemological Institute of America (GIA) and the American Gem Society (AGS) are the two most widely regarded and recognized diamond grading labs in the world.

And while there are many other diamond grading labs in operation Such as IGI, HRD, EGL, VGR, CGL, DGL, PGS. Different labs have different grading standards, and some labs will be more lenient with their standards than others. Therefore, we recommend buying from a diamond jewelry store that offers GIA or AGS certified diamonds, as these labs have consistently demonstrated their commitment to high standards. If you do elect to buy non GIA- or AGS- certified diamonds, always ask for credentials of the certifying lab.

Why Do We Need a Certificate?

Shopping for certified diamonds allows you to make an informed choice about your diamond selections and to comparison shop among various diamond merchants. You can compare one diamond with a particular weight and quality with other diamonds of similar weight and quality to determine which diamond is the better value -- or which merchant has the best prices.

What is Luster in Diamond?

The physical characteristic of diamond is adamantine -- brilliant light-reflecting and transmitting properties -- to waxy.

The luster of diamond is 'adamantine to waxy' -- a description of the scientific physical characteristic.

Luster is the clarity and refractivity of a particular stone. Not all diamonds are created equal. Flawless diamonds are extremely rare and prohibitively expensive for most of us. In jewelry, we usally have VVSI (very very slightly included), to SI2 (slightly included 2): the latter being generally the lowest grade for gem-quality diamonds. Inclusions can be any imperfection.

Luster refers to how well an object shines or reflects light. It is a property that can be used to describe rocks, etc.

In this case it is referring to how well a diamond reflects the light.

Luster is a mineral's refractiveness. Its ability to bounce back available light from inside. This can be affected by the color, cut or clarity of a gem-stone quality diamond. (Only 20% of all diamonds are gem-stone quality.)

The physical characteristic of diamond, the mineral, is adamantine – brilliant light-reflecting and transmitting properties -- to waxy

Treatment

Diamond treatments is performed on natural diamonds (usually those already cut and polished into gems), which are designed to improve the gemological characteristics — and therefore the value — of the stone in one or more ways. These include clarity treatments such as laser drilling to remove inclusions, application of sealants to fill cracks, color treatments to improve a white diamond's color grade, and treatments to give fancy color to a white or off-color diamond.

Following are various diamond treatment.

Clarity enhanced: diamonds are occasionally laser drilled to eliminate dark inclusions. Occasionally some diamonds are fracture filled with a foreign substance, which has good stability except during repair. Fracture filled is the process by which a substance of the same optical density as that of a gemstone is pressure filled into a fracture of that gemstone. These diamonds are called clarity enhanced and must be disclosed.

Irradiation: irradiation of diamonds has been around for a long time and uses a nuclear reactor or linear accelerator to create fancy colored stones. These are generally over colored and then annealed or heated to soften the shade back to a desirable and permanent color. Such treatments need to be disclosed by merchants/vendors as well as labs, it is illegal not to.

HPHT process: this process, using a high pressure/high temperature process (HPHT), changes inexpensively brown diamonds into near colorless white diamonds worth more than twice as much.

Diamond Cutting Process

Diamond cutting is the practice of changing a diamond from a rough stone into polished diamond (faceted gem). Cutting diamond requires specialized knowledge, tools, equipment, and techniques because of its extreme difficulty.

The diamond cutting process includes these steps; planning, cleaving or sawing, bruting, polishing, and final inspection.

Planning

Planning is a crucial step in diamond manufacturing because during this stage the size and relative value of the cut stones that the rough will produce are determined. A person called a planner decides where to mark the diamond rough for fashioning into the most profitable polished gem(s). The planner must consider the size, clarity and crystal direction when deciding where to mark the diamond rough. Incorrectly marking a diamond by a fraction of a millimeter can make a difference of thousands of dollars in some cases. In addition, if one attempts to cleave a diamond in the wrong position, the diamond could shatter and become worthless.

Maximize Value

The process of maximizing the value of finished diamonds, from a rough diamond into a polished gemstone, is both an art and a science. The choice of cut is influenced by many factors. Market factors include the exponential increase in value of diamonds as weight increases, referred to as weight retention, and the popularity of certain shapes amongst consumers. Physical factors include the original shape of the rough stone, and location of the inclusions and flaws to be eliminated.

Weight retention

The weight retention analysis studies the diamond rough to find the best combination of finished stones as it relates to per carat value. For instance, a 2.20 carat (440 mg) octahedron may produce (i) either two half carat (100 mg) diamonds whose combined value may be higher than that of (ii) a 0.80 carat (160 mg) diamond + 0.30 carat (60 mg) diamond that could be cut from the same rough diamond.

Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight, about 50%.Sometimes the cutters compromise and accept lesser proportions and symmetry in order to avoid inclusions or to preserve the weight. Since the per-carat price of a diamond shifts around key milestones (such as 1.00 carat), many one-carat (200 mg) diamonds are the result of compromising Cut quality for Carat weight.

Color retention

In colored diamonds, cutting can influence the color grade of the diamond, thereby raising its value. Certain cut shapes are used to intensify the color of the diamond. The radiant cut is an example of this type of cut.

Natural green color diamonds most often have merely a surface coloration caused by natural irradiation, which does not extend through the stone. For this reason green diamonds are cut with significant portions of the original rough diamond's surface (naturals) left on the finished gem. It is these naturals that provide the color to the diamond.

Turnaround minimization

The other consideration of diamond planning is how quickly a diamond will sell. This consideration is often unique to the type of manufacturer. While a certain cutting plan may yield a better value, a different plan may yield diamonds that will sell sooner, and thereby returning the investment sooner.

Cleaving or sawing

Cleaving is the separation of a piece of diamond rough into separate pieces, to be finished as separate gems. Once the planner decides where the diamond should be cut, the diamond is either manually cleaved or sawed. Sawing is the use of a diamond saw or laser to cut the diamond rough into separate pieces. can be done with a diamond-coated rotary saw or a laser.

Bruting

Bruting is the process whereby two diamonds are set onto spinning axles turning in opposite directions, which are then set to grind against each other to shape each diamond into a round shape. Bruting forms the basic face-up outline of a round diamond to prepare it for faceting. During the bruting phase the diamond being bruted is spun on a rotating lathe while another diamond is forced against it, gradually forming the rounded outline. Essentially, one diamond is used to shape the other. This can also be known as girdling.

Polishing

Polishing is the final stage of the cutting process, giving the diamond its finished proportions. The first and perhaps most crucial polishing stage is blocking. This step lays the foundation for the potential of the diamond's performance because it establishes the diamond's basic symmetry. During the blocking stage, the first 17 or 18 facets are made, creating a single cut. For some very small diamonds, the process stops here. Larger diamonds go on to the brillianteering stage. In this process a specialist called a brillianteer, polishes the final facets. It is this stage that will determine how much brilliance and fire a diamond displays. Minor inconsistencies in symmetry and proportions can make the difference between a gorgeous diamond and a dull, lifeless stone. The Hearts and Arrows in our beautiful diamonds are the result of a skilled and mastered brillianteer.

Final Inspection and Grading

A diamond's cost is based on the characteristics known as the "4 C's". Clarity, Colour and Cut (proportion) are the quality elements which together with the Carat Weight determine the value of a stone. The closer a diamond grades to the left of one or all of these scales the rarer and the more costly it will be. While clarity is frequently assumed to be the most important factor of all the "C's", in fact, colour and cut (especially cut) have a more profound affect on the visual appearance of a diamond.