Diamond Knowledge

Diamond, is derived from the ancient Greek "adámas", meaning unalterable and unbreakable. Diamond is a perfect combination of beauty, durability and rarity. Renowned for being the hardest substance on Earth, its ability to bring about admirable brilliance and fire makes it the most precious gem for mankind.   Diamond is formed deep beneath the earth's crust under extreme heat and pressure hundred millions of years ago. Such intricacy in its formation has crowned it the emblem for eternity. Appreciation of its splendor dates back to centuries BC and only royalty would have the authority to own diamonds as a symbol of highness in the old times. Today, people regard diamond as a symbol of timeless love and romance.

What is a GIA certificate? What is its role?

The GIA certificate, or the GIA Diamond Grading Report, is an identification certificate issued by the Gemological Institute of America (GIA). It serves as the basis for the sale and purchase of diamonds all over the world and is recognized by international diamond dealers as the most credible certification in use today. GIA assesses and grades each diamond before issuing a GIA Diamond Grading Report which accurately reflects its quality, thereby protecting the interests of buyers.

GIA Diamond Grading Report

Like a diamond ID, the GIA Diamond Grading Report is a detailed record of the quality of the diamond based on the 4Cs of diamond grading, including Carat, Color, Clarity and Cut, as well as fluorescence reactions, size ratios and so on. Some grading reports will be accompanied by a diagram of inclusions (this is more common for diamonds of more than one carat). Since diamonds are an expensive investment, all loose diamonds of more than 0.3carats sold by Diamania come with GIA Diamond Grading Reports to give our customers confidence and peace of mind. We advise customers to avoid purchasing diamonds that do not come with a diamond certificate at the time of sale.


Every diamond of more than one carat comes with a Diamond Grading Report that offers a record of its weight, grade, proportions and the most important diamond inclusions and blemishes. The nature, position, size, quantity and relief of clarity characteristics are also considered.  GIA Diamond Grading Report features a diamond report number and certificate laser barcode, providing effective and complete identification of each diamond.

Diamonds below one carat come with Diamond Dossiers that do not include a diagram of diamond inclusions.




The unique GIA Report Registry number of all loose diamonds above 0.3carats can be micro-laser inscribed onto the diamond’s girdle. Customers will be provided with a magnifying glass to verify for themselves that the diamonds are GIA certified and that the Diamond Grading Report corresponds with the diamond they purchase.

Checking GIA Diamond Grading Reports

An online service (at https://www.gia.edu/report-check-landing) is available at the official GIA website which customers can use to check the authenticity and accuracy of their GIA Diamond Grading Report and Diamond Dossier. All customers need to do is enter their GIA certificate number on the website or scan the QR Code on the certificate to locate the details. At present, this service is only available for diamonds graded from the year 2000.


A GIA laboratory has been set up in Hong Kong to provide customers with the ability to check all GIA-certified diamonds. It verifies that the customer has received GIA Diamond Grading Report corresponds with the diamond he/she has purchased, thus safeguarding the interests of the customer and providing them with confidence in the value of the diamond they have purchased. Please note that the service takes approximately two weeks and customers who use this service will settle the cost of the service directly with GIA. More, this service is not available for all mounted diamonds. Relevant details and fees could be found here.

Diamonds can be divided into many different shapes, the most familiar being round, heart and pear. Different shapes of diamonds can effectively reflect and refract the incoming light through different cutting methods and proportions, thus highlighting the unique charm and radiance of individual shapes.


Among the many shapes, the most widely sought after is Round Brilliant. The value of Round Brilliant diamonds, therefore, is relatively high, mainly because they are cut to achieve perfect symmetry and proportion. This ensures maximum brilliance, sparkle and fire. Fancy-shaped diamonds, that is, all non-round cut diamonds, include Princess, Emerald, Cushion, Pear, Heart, Oval, Marquise, Asscher and Radiant.


There is no such thing as a ‘best’ diamond shape. It depends purely on personal preference, and the shape that you find most attractive is your best choice. Diamania has a large inventory of diamonds, which includes a wide variety of shapes in addition to the most common round cuts, to meet the needs and preferences of different customers.

Different Diamond Shapes

  • - Please view as below -
  • Round Brilliant
  • Princess
  • Emerald
  • Asscher
  • Marquise
  • Oval
  • Radiant
  • Pear
  • Heart
  • Cushion

Round Brilliant

In the past century, Round Brilliant has been the most popular and most studied diamond shape, and the most demanding shape for lapidarists.


The Round Brilliant cut was born in 1919. It was a Belgian diamond cutter Marcel Tolkowsky who considered the refractive response of diamonds and light and the spectral theory that influenced the radiance, accurately calculating the perfect cutting ratio and symmetry. Round brilliant cut has 57-58 facets to ensure diamonds shine and sparkle better than any other cuts. It has become the diamond design for the ring finger for millions of people.


The most significant benefit of Round Brilliant diamonds is that they offer a higher flexibility in balancing cutting. Skilled cutting can also make up for the lack of color and clarity. At the same time, they have the brightness and fire that customers hope to achieve. In Hong Kong, almost 90% of customers choose Round Brilliant diamonds. It should be noted that in the case of the same weight, Round Brilliant diamonds will appear larger and come at a relatively higher price than diamonds of other shapes.



Among non-round diamonds, the most popular shape is the Princess cut. It is frequently selected for engagement rings thanks to its beautiful brilliance and unique cutting. The Princess cut has sharp corners and is traditionally square or rectangular.


The Princess cut was first seen in the 1980s. It consists of 76 facets. Its biggest advantage is its contemporary style. It also has a brightness that is equivalent to the round brilliant diamond. As for its shape, the Princess cut is considered more unique and fashionable.


An important point to note is that Princess-cut diamonds with a lower color grade will have a more concentrated color at their sharp corners. As such, we recommend that you choose a higher color grade for your Princess-cut diamond.



One of the most classic shapes, Emerald-cut diamonds are typically cut into rectangles.


The Emerald shape is unique for its large open pavilion, which is cut into rectangular facets to create a distinctive optical visual appearance. Compared to other shapes, the Emerald-cut diamond is surrounded by a stepped cut surface, which is more classical and elegant.


As inclusions, external flaws, and color are particularly visible on the large, smooth surface of an Emerald-cut diamond, high grades of color and clarity are especially important.



Cushion-cut diamonds, also known as pillow-shaped diamonds, are an enduring and popular diamond shape. Cushion-cut diamonds were the most sought after diamonds before Round Brilliant diamonds took center stage.


Cushion-cut diamonds come in different shapes, including square and rectangular with rounded corners. With their relatively large facets, Cushion-cut diamonds can appear as brilliant as Round Brilliant diamonds.


The Cushion-cut diamond is similar to the radiant shape, and features an even distribution of color, making it a popular shape choice for the colored diamond. However, as large cut surfaces make inclusions and external flaws more conspicuous, customers who have a soft spot for cushion diamonds should choose a high clarity grade.



Pear-shaped diamonds combine a single tip with a round bottom design, and are also known as Teardrop-shaped diamonds. The Pear shape is selected for its elegance and dignified feel. Pear-shaped diamonds are worn with their sharp corners directed toward the fingertips. A slender Pear shape can make your fingers look slimmer and more beautiful. This unique shape is also often used on pendant earrings.


Pear-shaped diamonds are cut in such a way that they have a bow-tie shadow at the bottom of the center, called the “bow-tie effect”. The smaller the bow-tie shadow is, the better. The most traditional Pear-shaped diamonds have a long-to-wide ratio of between 1.4 and 1.6.



The Heart shape comes second only to Round Brilliant in terms of popularity among couples who view the Heart shape as a symbol of love and romance. It is especially suitable for a marriage proposal or an expression of love.


This shape is an adaptation of the Round Brilliant, featuring complete symmetry, equal curvature, and open cuts. As the color of the Heart-shaped diamond is concentrated in the corner, it is better to choose a diamond with a high color grade.


The aspect ratio of a Heart-shaped diamond is generally between 0.80 and 0.95.



The Oval diamond has the same faceting and design concept as the Round Brilliant; but as its shape is elongated, it can make the wearer’s fingers look slimmer and more slender. It is suitable for some people who desire a round cut but who hope to achieve a longer and more slender effect.


Although, like a Round Brilliant, this method of cutting increases the brightness of a diamond, if the cutting is insufficiently precise, or the craftsman less skilled, a bow-tie shadow is likely to appear at the center of the Oval diamond. This is called the “bow-tie effect”.


The aspect ratio of Oval-cut diamonds is between 1.33 and 1.66.



The Marquise cut is said to have been named for Marquise de Pompadour, the mistress of King Louis XV of France. It resembles the shape of her lips. Thanks to its elongated shape, the Marquise diamond appears larger than it is, while its length makes the fingers look slimmer and younger. Fine stones are usually placed on both sides to highlight the slender shape.


Like some other fancy-cut diamonds, Marquise diamonds also have a bow tie effect. This pattern is usually seen where the diamond is at its widest, along the center of the table. The better the cut, the smaller the bow of the Marquise and the better the contrast inside the diamond.


The length-to-width ratio of Marquise-cut diamonds lies between 1.75 and 2.25.



The Asscher diamond’s appearance is very similar to that of the Emerald shape. Asscher diamonds are square and have a large stepped cutting surface with obvious corner effects. As the color of the corners of Asscher are more conspicuous, diamonds with a higher grade of color should be purchased.


The clarity of a diamond is well-highlighted by the Asscher shape which offers a higher degree of reflection than the Emerald-shaped diamond. Its flare is more dazzling, and its shape is elegant and noble.



At first glance, the Radiant-shaped diamond has a similar appearance to the Emerald shape, but its crown and pavilion feature a mix of stepped cuts and brilliant cuts, giving it a more glittering, sparkle effect than the Emerald shape.


The most outstanding feature of the Radiant diamond is its angle of repair. The Radiant cut diamond with a rectangular or round auxiliary stone is also very beautiful, as its unique shape improves the color effect. Radiant is the ideal cutting choice for a colored diamond.


The aspect ratio of a Radiant diamond is between 1.00 and 1.40.


What does ‘carat’ mean? Where did the term originate?

Carat, abbreviated in English as “ct”, originated in Greek – Kerátion. The word was adapted from “Carob”, the name for long horned beans. In the early days, gem traders used small bean seeds of the same weight as weights for the scale, so “carat” became the representative word for the weight of the diamond. Many people misunderstand the term “carat” as referring to a diamond’s size, but in fact refers to its weight. Today, carat is the world’s most common gem weight unit.


1 carat equals 200 milligrams, or 0.2 grams. 1 carat is divided into 100 points, so 0.50 carat is 50 points. Note that even a minor variation in carat weight would mean a considerable difference in cost, so accurate diamond weight is important. In general, weight is often measured into one of thousands of carats and rounded to 0.01 carats (e.g. 1.01cts).

Carat and price

The carat of a diamond directly affects its price, but not in a simple positive ratio. Because high-quality large carat diamonds are extremely rare, the price of diamonds of the same grade in terms of color, clarity, and cut multiplies exponentially with an increase in carat weight. A one-carat diamond is far more expensive than two 0.50cts diamonds of the same quality. The price of a diamond will jump at a specific weight (0.30cts, 0.50cts, 0.70cts, 1.00cts, 1.50cts, 2.00cts …). Therefore, if their budgets are a little tight, customers may consider buying a diamond that is slightly lower than a specific weight, for example 0.60cts, 0.90cts and so on, so that the visual size of the diamond can be close to the weight of the diamond selected in the heart, while maintaining a certain quality in the other three indicators of color, clarity and cut.


The size of a diamond is usually determined by measuring the diameter face-up as this would be the appearance once the diamond is mounted. Please use below tool for comparison of general diamond sizes of different carats.





The following diagram shows general diamond sizes with full cut from range of 0.25 to 3.0 carats.


However, the size of the same weight of diamonds may be slightly different to the average, due primarily to the cut. For example, a standard one-carat diamond is 6.4mm in diameter; but if the diamond is cut into a thicker shape, the top view will give the impression that the diamond is of a smaller size than the original diameter of 6.4mm. Therefore, in order to accurately calculate the size of the diamond, Diamania recommends considering both the carat and the cut grade at the same time.

What is the color of a diamond?

Diamond color refers to the degree of lack of color. The process of identifying the color of a diamond is actually concerned with identifying the color and transparency of the diamond. If a diamond is formed with 100% carbon, without any impurities and structurally intact, it should be completely colorless.


That said, almost all diamonds are formed with a small amount of impurities, such as nitrogen, boron, hydrogen or other elements, resulting in a certain degree of color tone. Nitrogen is the most common of the mixed elements, and it appears yellowish or light brown in lower quality diamonds. Therefore, in general, the more pure a diamond is, and the closer it is to the colorless diamond, the more rare and valuable it is. Fancy color diamond is a special case. The deeper and more obvious the color of a fancy color diamond, the higher its value.


GIA Color Grading Scale

Color grade D is the highest color grade. Roughly the top 1% of quality based on color. Color grades E and F have virtually no or undetectable amount of color. Extremely rare and valuable.
G-H:Near Colorless
Slight traces of color that are not noticeable to untrained eyes.
I-J:Near Colorless
Color is slightly noticeable, especially when examined face down.
K-M:Faint to Light Yellow / Brown
Color is noticeable.


Despite the fact that around 80% of customers prefer D-H color-graded diamonds, we suggest our clients to take budget and other factors (such as clarity, cut and fluorescence, etc.) into account when making decision. Please do not hesitate to make an appointment for our free consultation service on diamond selection.

Why does the GIA diamond color rating begin with D?

The GIA diamond color grading system has evolved over the years, going through many different types of hierarchical systems — some alphabetical (A represents the diamond of the highest quality); some sorted using Arabic numerals (0,1,2 …); some by Roman alphabet (I,II,III …).  As there were different shortcomings and loopholes in these systems, including inconsistencies and inaccuracies, GIA experts have created a new diamond color grading system, which goes from the letter D.

Related information regarding diamond color

The color of a diamond is affected by its background, making it easiest to discern against a transparent or white background. Therefore, if the diamond is inlaid on gold or rose gold, the color level requirements may be reduced, along with the budget. Also, as some fancy shapes keep a diamond’s color concentrated at corners, diamond cuts with sharp corners, such as heart-shaped, pear-shaped, marquise, and radiant diamonds, allow the color to be more easily detected. As such, when choosing a sharp-angled diamond, it is best to avoid choosing a diamond with a low color grade. Finally, we recommend that whenever you set more than one diamond or add side diamonds on a piece of jewelry, bearing in mind that each diamond should not have a color difference of more than one to two levels.

Natural diamonds, in the process of being formed by carbon element through high temperature, high pressure underground environment, naturally feature internal and surface defects, called ‘inclusions’ and ‘blemishes’, respectively. Natural, tiny imperfections do not affect the beauty of the diamond. On the contrary, these traces make each diamond unique.

What is diamond clarity? How is it graded?

Diamond clarity is one of the criteria for judging a diamond’s quality. Diamond clarity is graded by Nature, Position, Size, Quantity and Relief of clarity characteristics and surface features. These characteristics are like each diamond’s “birthmark”. Clarity refers to the purity of the diamond; the higher the clarity, the higher the value of the diamond.


As for the diamond inclusions, Pinpoint, Cloud, Crystal and Feather are common. The clarity of a diamond is graded using a 10x microscope and any inclusions that are detected at that magnification are generally not visible to the naked eye. At 10x magnification, almost no diamond is perfect, thus flawless diamonds are rare.

GIA Diamond Clarity Grading

Under the GIA Diamond Clarity Grading System, diamond clarity is divided into six levels, including Flawless (FL), Internally Flawless (IF), Very Very Slightly Included (VVS), Very Slightly Included (VS), Slightly Included (SI) and Included (I). External defects, on the other hand, refer to external impurities or imprints on a diamond’s surface, which have a very subtle effect on its hardness and structure. As such, the impact of blemishes on a diamond’s value, aesthetics and clarity level is generally small.


  • Flawless (FL) – Observed under a 10x magnifying glass, the diamond has no inclusions or blemishes.
  • Internally Flawless (IF) – Observed under a 10x magnifying glass, the diamond has no visible inclusions, only visible blemishes that only professional graders can see.
  • Very Very Slightly Included (VVS1 and VVS2) – Observed under a 10x magnifying glass, the diamond’s inclusions are difficult even for a professional grader to see.
  • Very Slight Included (VS1 and VS2) – Observed under a 10x magnifying glass, the diamond’s tiny inclusions range from difficult to see by professional graders to easier to see.
  • Slightly Included (SI1) – The diamond’s inclusions can be easily seen when viewed under a 10x magnifying glass, but most do not affect the front appearance and transparency of the diamond.
  • Slightly Included (SI2) – Observed under naked eye, the diamond’s inclusions are visible, but most do not affect the front appearance and transparency of the diamond.
  • Included (I1) –The diamond’s inclusions are clearly visible by naked eye and may affect transparency and brightness.
  • Included (I2 and I3) – The diamond’s inclusions are clearly visible by naked eye, and affect its transparency. Diamania does not sell diamonds at this clarity level.


GIA Diamond Grading Report for a one carat or above diamond is accompanied by a plotted diagram of its clarity characteristics. Markings in red represent internal inclusions, while indications in green represent external blemishes. This diagram serves as a very useful tool for distinguishing diamonds. In general, only inclusions which have a significant impact on a diamond’s clarity level will be indicated, while other inclusions will only be noted in the comments.


Here is a list of the characteristics that may appear on a plotting diagram, along with their corresponding symbols:


There are many types of inclusions, and the following are enlarged images and notes for each inclusion:


Crystal – Minerals hidden inside diamonds are the most common inclusions and can manifest in different sizes and colors.


Pinpoint – Tiny dots of crystals in a diamond are the slightest and most common inclusions.


Cloud – A cluster of pinpoints which are common inclusions. Each pinpoint in the cloud is too small to be individually discernible; however, serious ‘Cloud’ conditions can cause a diamond to have a hazy (“milky”) appearance. (Diamania does not sell “milky” diamonds)


Needle – A slender crystal shaped like a needle. This is a common, though very slight inclusion.


(The above four inclusions are caused by the mineral crystal, with differences in size, shape and range.)


Feather – A crack in the diamond which resembles a feather. Most of these common types of inclusions are minor. Large cracks (generally Si2 or below) have a risk of becoming larger and of having an impact on the structure of the diamond.


Knot – Another transparent diamond crystal touching the diamond facet. It is generally more common in SI-graded diamonds.


Cavity – A Corner Notch which may have been caused by the collapse of a small piece of diamond. It may also be a pit or hole caused by a crystal shedding on the surface of a diamond during the polishing process. It is generally more common in SI-graded diamonds.


Bruise – A mark formed by external force impact that extends from the surface of a diamond to the inside, generally seen at the junction of the facets. It is usually white, accompanied by cracks, and is relatively rare.


Natural – Where most of the rough stone skins retained at the girdle or near the girdle for maximum quality are irregular. More common in just 0.7cts, 1.0cts and 1.5cts.


Indented Natural – Part of the rough stone skin is sunken under the surface of the cut diamond, which is more pronounced than natural. It is more common in just 0.7cts, 1.0cts and 1.5cts.


Twinning Wisp – The center point of the crystal structure irregularity of the diamond, often accompanied by pinpoint inclusions. Generally more common in SI-graded diamonds.


Internal Graining / Surface Graining – These diamond growth marks are due to irregular growth of atoms.


Bearded Girdle – A whisker-like microcrack that exists at the girdle and looks like a beard. It is caused by excessive rough grinding and is rare.


Laser Drill Hole –  A microscopic tube that is present as a result of laser drilling. The process of laser drilling involves using laser to drill tiny holes all the way from its surface to an inclusion. This channel is then used to remove the inclusion by either melting with heat or dissolving with acid.


Etch Channel – A strip-shaped like a saw or a knife that extends from the surface. It goes from the surface to the most vulnerable position in the body of the rough by chemical or material erosion. It can be straight or curved and can be deep. Shallow versions are less common.


According to statistics, most customers will purchase diamonds with a clarity grading of VS or SI. However, if you intend to choose a diamond from diamonds with the same clarity grade, it is important to pay attention to the distribution and characteristics of the inclusions prior to purchase. For example, dispersed inclusions are more popular. If you wish to find the diamond that suits you best, you are welcome to make an appointment for a free consultation with Diamania.


Eye Clean – A diamond classified as ‘Eye Clean’ looks clear to the naked eye; i.e. its inclusions are not visible on the front side without the aid of a magnifying tool. Since each person’s vision is different and the guidelines are different, this definition is more subjective. Generally, diamonds are viewed from about six inches away by the naked eye. If the front side does not appear to have obvious inclusions, it may be called Eye Clean.


Almost all diamonds contain inclusions while traces of inclusions in diamonds of FL and IF grades are not detectable at 10x magnification. Many customers believe that VS and SI grades have the highest cost-performance ratio, because these grades are more affordable, meanwhile the inclusions and blemishes of VS and SI grade diamonds are typically not visible by naked eye. The brightness of a diamond may also be affected by the visibility of the inclusions and blemishes. The larger the facets of the diamond (such as an Emerald-cut diamond), the easier it is to examine its inclusions and blemishes. It follows then that if you want to buy a diamond with a large table or fewer facets, it would be wiser to select a clarity grade of VS or above.

What is the cut of a Diamond?

Diamond-Cut refers to the angle of the diamond facets, the proportion of each part of the diamond after cutting and the smoothness of each face. Its purpose is to allow the diamond to successfully condense and reflect most light. Cut is the most complex and technically demanding of the 4Cs. It has very high requirements regarding accuracy and measurement limits. It also pays attention to the results of polishing, because it directly affects the visual fineness of diamonds.


Although the color and clarity of a diamond are limited by its innate qualities, the exquisite craftsmanship of a diamond’s cut and finish is necessary to reveal a diamond’s total beauty. Among the 4Cs, cut has the greatest influence on scintillation, brightness and fire of a diamond. If not properly cut and polished, even flawless high-color diamonds would look dull.

Diamond cut categories

The factors of Cut, Polish and Symmetry work together to determine the ideal light reflection of the diamond.


Cut – The scale of each facet or proportion of the diamond. Since the scale of each facet, angles and proportion of every diamond is calculated, it needs a suitable standard size to achieve the best internal reflection and refraction to produce beautiful color beams.

Polish – The smoothness of the surface. The smoother the surface, the stronger the surface reflection.


Symmetry – The degree to which each facet of a symmetrical or full-grain diamond is cut neatly, such as whether the shape of the circumference is a perfect circle, whether there is a deformed facet, or whether the table is parallel to the bottom.


The above three factors have five levels in GIA.

The highest is Excellent (EX), followed by Very Good (VG), Good (G), Fair (F), and the worst is Poor (P)

The importance of cut

The cut of a diamond directly affects the angle and direction of light entering our eyes, and thus the degree of sparkle. A high-quality diamond should have a precise ratio and excellent symmetry, so that the light entering the diamond can be internally reflected by different facets and redistributed into a color spectrum, which is finally refracted from the top. Diamonds can shine with dazzling brilliance. If a diamond is cut too deep or too shallow, the light will not be effectively refracted back to the top, but will leak from the side or bottom, reducing the diamond’s brilliance and rendering it relatively dim. This ultimately lowers the value of the stone.


The cut proportion

The cut proportion of a diamond refers to the relationship between the size and angle of its polished facets. While there is an ideal cut proportion for each diamond, there is no fixed “formula” or proportional value. The ratio is a magical factor that GIA researchers have discovered from more than 70,000 observational tests during the development of the cut grading system. Compared to any single ratio combination, the GIA system places more emphasis on the overall appearance of the diamond. Each cut grade has a certain proportion range, and each diamond at a cut grade will have visual differences, which are reflected in the fire, brightness or pattern. Therefore, a particular diamond may be more attractive to one customer than it is to another, although both customers are equally discerning.


Optical effects

The sparkling brilliance of diamonds is the result of optical effects. When light enters the diamond, it effectively gives life to the diamond, directly affecting its visual appeal, especially as the process of moving the diamond is more obvious. The following are terms related to optical effects:


Brilliance – Refers to all white light reflections on the outside and inside of the diamond. Diffuse illumination (that is, when the incident light is not from a single direction) is the best measure of brightness. Even if the carat, color and clarity are the same, the brightness of a cut diamond will be greater than a non-cut one. In general, the greater the brightness of a diamond, the higher its cut level.


Fire – When white light passes through a diamond, it disperses into a rainbow-like spectral color, creating a fire. In the store’s spotlight, you can see a red, orange, yellow or blue beam flickering as you rock the diamond.


Scintillation – The result of brilliance and pattern combined. This refers to the spot that flashes when a diamond, person, or light source moves. A high-quality diamond’s light reflection should be uniform and of appropriate size.


Pattern – Refers to the relative size, arrangement and external and internal reflection of a diamond, which create a contrast between light and dark areas. The light and dark areas of the diamond must have sufficient contrast to form a clear and degraded pattern, while ensuring dark areas are not overshadowed.

What is ‘Hearts and Arrows’?

‘Hearts and Arrows’ is a mark that was developed by the Antwerp Diamond Appraisal Agency in 2009 and is regarded as one of the criteria for verifying diamonds. The pattern of the heart and the arrow is a symmetrical optical figure obtained by observing the cutting of a round diamond with a special instrument.


The round brilliant cut diamond has 57 facets. When all the facets reach the symmetrical and specific scale range, the diamond will show a pattern of eight arrows when viewed from above. You will also be able to see eight heart-shaped patterns at the bottom of the diamond. All of these ‘hearts’ and ‘arrows’ are almost exactly the same and nearly perfect.


Many people misunderstand the ‘Hearts and Arrows’ mark as indicating a perfect lathe, but it is just a sales strategy adopted by jewelers in the 1990s. It is thought to represent the human heart, with the arrow symbolizing the cutting of the diamond. It draws from the mythical story of Cupid, the god of love, and used to make the diamond a symbol of pure love. Since the cutting method for all Round Brilliant diamonds is standardized, GIA cuts and symmetry ratings of Excellent, Very Good or Good can achieve different levels of the ‘Hearts and Arrows’ effect.


What is diamond fluorescence?

Diamond Fluorescence refers to the blue light or other colors of light emitted by a diamond under intense ultraviolet light. It is created when the electrons of a diamond are stimulated by high frequency energy, which is forwarded into light energy to emit visible light.


In normal daylight, most of a diamond’s fluorescence is not noticeable, as it is only visible when a diamond is exposed to ultraviolet light at a close distance. However, fluorescent light also has a certain impact on the value a diamond. Some diamonds with strong fluorescence for example, will see their transparency decrease, making them appear white. In a GIA diamond grading report, a description of the fluorescence is generally recorded. According to GIA statistics, about 25%-35% will show different degrees of fluorescence, 90% of which emit blue light, while the rest emit other colors, such as yellow, red, orange, white and green light.

Levels of fluorescence

(1) None
(2) Faint
(3) Medium
(4) Strong
(5) Very Strong


The effect of fluorescent reactions on diamonds

Fluorescent reactions can affect diamonds in the following ways:


Diamonds of D-I color – The stronger the fluorescence, the greater the chance that the diamond will appear cloudy. As this affects its fire, it will negatively impact its price.


Diamonds of J color or below – Diamonds of the same color, visually, may be whiter with fluorescent light.

The advantages of fluorescent diamonds

Compared to the remaining 4C factors, the Faint or Medium level of fluorescence has less impact on the appearance of a diamond, and the price of a fluorescent diamond is generally lower in any color, making it suitable for customers with lower budgets. In addition, people select and purchase diamonds based on personal preferences, and a small number of customers are attracted by these interesting features.

What is colored diamond? What is the difference between colored diamond and any other diamonds?

The hues of colored diamonds are the colors that cannot be naturally absorbed. Colored diamonds are rare. The biggest difference between colored diamond and white or transparent diamond is that they have very different colors scale and grading standards. Clarity and cutting are very important when choosing normal diamonds while for colored diamonds, it is more about hues, tones and saturation. Unlike other diamonds, the more intense of the hues, the higher the value.

The hues of colored diamonds

If the hue of the diamond comes in every colour of the rainbow spectrum, the diamond is highly valued and precious.


Due to its uniqueness and preciousness, colored diamond has been under the spotlight and reported by media. The price of colored diamond often breaks auction house’s record and some even considered to be rarer than any diamond rated D-to-Z grading spectrum.

Diamond requires billions of carbon atoms to bond, affected by natural radiation and other natural factors, colored diamond is formed. Every single colored diamond is unique in its colour. Only 1 in 10,000 diamonds is a colored diamond and only 1 in 25,000 diamonds can be categorized as fancy diamond. Among all colored diamonds, yellow and brown diamonds are relatively less precious while red, pink, green or blue diamonds are considered rare.


Under usual circumstance, there is another grading standard to grade colored diamonds and they usually have a higher value than white diamond. After years of research and verification, GIA has been able to formulate a reliable evaluation system to grade rare colored diamonds. The system has been widely used and followed by almost every auction house.  Below are the terms GIA use to grade colored diamonds:

Faint / Very Light / Light / Fancy Light / Fancy / Fancy Dark / Fancy Intense / Fancy Deep / Fancy Vivid

Factors to be considered when choosing colored diamonds

When choosing colored diamonds, it is more important to consider the hue and saturation of the color than its clarity and cutting. The richer its hue, the higher its value and rarity.


Second comes to the carat of the diamond. Even though it comes second however, carat still affect the value of the colored diamond. It is less likely to find big diamonds than small diamonds during the mining process. Big diamonds are rarer hence higher the value. And the price of a colored diamond could be doubled or tripled according to its carat weight.


The reason why clarity and cutting are not as important to colored diamond is that the color would cover the inclusion in the diamond. Therefore, the importance of clarity is reduced. Moreover, the cut of the diamond helps to reflect the fire and flicker of the diamond while colored diamond is all about the color. In some cases, natural colors may detract from its flicker and many colored diamonds are cut into unconventional shapes in order to enhance the color.

How to pick the color?

The best way to set the colored diamond is to choose a material that can help to enhance the natural colors of the diamond.


For example, gold is often used to set yellow diamonds while it looks best to use rose gold to set pink diamonds.


Yellow – People usually choose yellow diamond as their first colored diamond. The carbon atoms in the diamond are replaced by nitrogen atoms and hence the yellow is formed after absorbing the blue and purple during the formation process.


As nitrogen atoms are similar enough to carbon atoms that they easily take carbon’s place in the formation process and the yellow is formed after absorbing the blue and purple during the process. The proportion of nitrogen atoms in the diamond defines the richness of the yellow. While the hue of the yellow is outside the D-to-Z grading spectrum, it will be considered as colored diamond.



Since most of the white diamonds contain a slight yellow hue, the yellow diamonds come in a relatively large quantity and cheaper than other colored diamonds. However, the most beautiful and eye-catching yellow diamonds can be more precious than the transparent D-grade diamonds.


Pink – Charming pink diamonds. Pink gives an impression of romantic and charming and pink diamond is the rarest among all colored diamonds. Pink diamonds constitute less than 1% of the total quantity of diamonds so it is one of the most highly valued fancy color diamonds. Pink diamonds are mostly mined in western Australia and Brazil. The pink shades are formed due to the abnormal electron structure and deformation on the surface.


Blue – A fancy blue diamond can be highly valued as well. The boron in the carbon allows electricity to pass hence the formation of the beautiful blue. The hue of the natural blue diamond comes from the boron. The higher the boron concentration the stronger the hue of the blue. But the blue can be also caused by radiation or hydrogen. India used be the most important minefield of blue diamond but in the past few years people have found some very famous blue diamonds in Cullinan, South Africa.


Green – The elegant green diamonds, unlike other colored diamonds, are formed after million years of absorbing natural, harmless radiation. The green diamonds are precious because it takes million years to form. Green diamonds come in various hues, can be dark or light. when radiation enters the diamond, it knocks the carbon atoms out of their position in the crystal lattice, hence the change of color. This often happens when the mind field is near radioactive rocks and natural green diamonds are extremely rare.


Orange – Orange diamonds are very unique. Citrus and amber hue are not rarest among natural diamonds but pure orange diamond is extremely rare. The orange implies the diamonds contain a great amount of nitrogen.


Black – The Deep black diamonds. Most of the natural black diamonds are formed because they contain lots of inclusions for example graphite, pyrite or hematite. Of course, some diamonds might be full of black cracks and fractures or turned into black because of graphitization. What can be certain is that these inclusions are the reason behind the black colour. However, the actual colors of natural black diamonds come in a wide range from almost colorless to brown or olive green.


Red – Red diamonds is rarest among all colored diamonds. Until now it is still very rare to find any red diamonds weight more than 5 carat. From 1957 to 1987, GIA has never certified any red diamonds. The red shades are formed due to the abnormal electron structure and deformation on the surface.

There are several methods you may use to verify the authenticity of a diamond:

Select a merchant that provides a diamond grading report for every diamond purchased

GIA Grading Reports will clearly list the grade and weight of the diamond. Certificates of 1 carat or more will generally be accompanied by a drawing of the diamond itself and a map of its inclusions. A magnifying glass can be used to compare the GIA number and inclusions on the diamond with the information on the certificate to determine the authenticity of the diamond. GIA also uploads the certificate of each identified diamond to its official website. The customer only needs to enter the GIA number to determine the authenticity of the certificate.

Use a diamond tester

Thermal conductivity refers to the ability of materials to directly conduct thermal energy. Due to the high thermal conductivity of diamonds, the use of a diamond thermal conductivity tester is a fast and accurate method. It can instantly test diamonds of various sizes and shapes. When the instrument is in direct contact with the diamond surface, it will immediately mark it as true and false. The new tester pen can easily distinguish the most similar diamond simulant Moissanite.


In addition, the Gemological Institute of America (GIA) has set up a laboratory in Hong Kong where customers can review or check their GIA Diamond Certificates as well as verify the authenticity of the GIA Diamond Certificates they receive and of the diamonds they purchase. This protects the interests of customers and gives them confidence. Please note that the services take approximately two weeks. The service typically costs a few hundred Hong Kong dollars and payment is settled directly with GIA. For more details of services and fees, please visit https://www.gia.edu/doc/DtoZ_FS_HKD_2019_1001.pdf.


There are also many seemingly simple and quick ways to verify the authenticity of diamonds. Some of these, however, are not recommended, such as refraction test (the diamond is placed face down on white paper with black lines), fog test (lightly sigh on the surface of the diamond) and hardness test (light stroke on the surface of the diamond with a pen). As these methods are neither precise nor accurate, their results are not credible, and we do not recommend these tests.

Store diamond jewelry with care

Although diamonds have a high hardness, it does not mean that they cannot be scratched by other diamond ornaments. To keep your diamond in its best condition, do not store it with other jewelry in the drawer or jewelry box. Avoid friction as this can cause a diamond to appear worn. We recommend that customers use a soft fabric to wrap each piece of diamond jewelry and store diamond jewelry separately in accessory bags to reduce the risk of scratching and abrasion.

Keep away from corrosive substances / chlorides

Do not expose diamond jewelry to chemicals, such as common household bleach, acidic cleaning solutions or even chlorine. This means extra care should be taken when performing household chores or swimming, as these chemicals can weaken the metal in jewelry, causing the diamond to fall off.

Reduce exposure to cosmetics and oils

Diamonds have an oily nature, making them prone to collecting grease or other dirt as a wearer goes about his/her daily life.  The use of cosmetics, lotions or perfumes may cause the diamond surface to become dull and dark, affecting its luster. Avoid touching and playing with a diamond ring, as the grease on your fingers will reduce its brilliance and affect its appearance. If you accidentally stain the diamond, we recommend mixing a small amount of neutral detergent with water and soaking the affected diamond jewelry. Remove after a few minutes and gently clean the diamond and the holder with a soft brush. Finally, rinse once again with clean water and dry with a soft cloth.

Clean diamonds regularly

To preserve and maintain diamonds for long periods of time, daily cleaning procedures are important. We recommend that you purchase a bottle of jewelry-specific cleaning solution and follow the instructions closely to clean the diamonds and keep them in their best condition.


First, place the gemstone jewelry in the diluted soap solution and gently clean the gemstone and its setting with a soft brush. Rinse with clean water and use a soft lint free cloth to dry the surface. Remember to plug the sink or use a basin to prevent the jewelry from falling into the drain.


Cleaning instructional videos: https://youtu.be/qCoKpmH7mlE


Ultrasonic cleaning methods may not be suitable for some gems such as cracked jade, emerald and opal, because the ultrasonic machine may shatter the gemstone and cause it to break. For these, it is sufficient to simply wipe with a soft dry cloth. Fingerprints and stains on the surface of the precious metal can be removed with a non-abrasive cloth such as a silver cloth or a spectacles cloth.

Come to us for professional cleaning

Our customers are always welcome to visit our store for regular ultrasonic cleaning to keep the jewelry new and shiny. Enjoy the service that you deserve!

How to select an engagement ring?

Everyone has different styles and requirements for the ring. Before choosing a ring, you may want to pay close attention to your partner’s hobbies. We generally recommend that customers begin by looking at the intended wearer’s daily life. Pay attention to the type of accessories that he/she wears more regularly. Are they more regal and glamorous? Or more low-key and elegant? Customers may also seek the advice of close family members or friends. Before purchasing an engagement ring, they should have a general understanding of the intended wearer’s preferences. If there is no concept of preference, customers will generally select a simple and classic ring style, which is the easiest to match.

What budget should be set?

A marriage proposal is a sacred ritual that combines an expression of love with a lifelong promise to care for the intended. It is of tremendous value, regardless of the monetary cost of the ring. The most important thing is to ensure the intended feels your determination and sincerity.


If a customer has no idea on what budget to set for the engagement ring, according to past experience, our customers will spend an average of one to two months’ salary on this purchase.

Where is the engagement ring worn?

Since ancient times, the ring has represented a vow of love. However, where the ring is worn is different in different cultures. Western tradition believes that the left hand is connected to the heart, so the wedding and engagement rings are generally worn on the left hand, and the engagement ring is placed on the ring finger of the left hand when the marriage proposal is made. In Hong Kong, the engagement ring is usually worn in the middle finger of the left hand, while the wedding ring is worn on the ring finger of the left hand.

How to measure ring size?

The following are some methods for which accuracy is low, for reference:

Finger Size Estimation

You can examine your partner’s finger to approximate the estimated size and refer to the ring diameter conversion chart. The average middle finger size for Hong Kong women is 12 to 14 laps.

Measuring Line Length

You can measure your partner’s finger circumference with a string or note. First, around the root of the partner’s finger, then draw a mark at the intersection with a pen, then measure the length of the rope or strip with a ruler, and then select the closest ring size on the ring size meter. Of course, all this must be done while your partner is soundly asleep.

Higher Accuracy Method:

Existing Ring

If your partner already wears a ring, try wearing it on your finger for comparison, or give us a direct measurement! But there are some differences between the main fingers and the left and right hands.

Borrow Our Plastic Ring Sizer

We have different sizes of rubber ring which you can loan for free! Measure without your partner’s knowledge!


If you are not confident about the ring size we recommend ordering a larger size than the estimated one, to ensure that the engagement ring can be put on during the proposal.


Rest assured that you can enjoy a free ring re-sizing service after purchasing a diamond ring at Diamania. You can change the size at any time after your successful proposal.