Natural Diamond Academy
4Cs of Diamond Quality
Carat
Diamonds are weighed by carat. 1 Carat equals to 200 Milligrams, namely 0.2 Grams. 1 Carat can be divided into 100 Cents, which are also known as Points. So 0.75 Carat is equal to 75 Cents, while 0.01 Carat is the same as 1 Cent.
The value of diamonds is not calculated on a per cent basis. Under other similar conditions, the value of diamonds can increase geometrically as the weight of diamonds increases. On the other hand, the values of diamonds of equal weight could be very different depending on their colour, clarity, and cut.
Natural diamonds with excellent quality can be found in different sizes and shapes, we suggest customers to look for their ideal items based on budget, size, quality and styles.
Diamond ring analog scale
Clarity
Every natural diamond contains natural inclusions, for instance naturally occurring blemishes. The quantity, size, shape and colour of these inclusions determine the clarity and uniqueness of a diamond. Inclusions are embedded inside a diamond and can be white, black, opaque, or even green or red in colour.
Clarity is the system that measures the quantity of inclusions and blemishes in a diamond, ranging from Flawless/Internally Flawless to Included. Most inclusions cannot be seen by the unaided eye and can only be observed by 10-Power (10X) magnification by a skilled grader. However, blemishes in diamonds of the Included grade can be observed by the unaided eye.
VVS1 - VVS2
Very Very Small Inclusions
VS1 - VS2
Very Small Inclusions
SI1 - SI2
Small Inclusions
Colour
Diamond colours fall into two categories. Colourless diamonds can be clear, or have a hint of faint yellow or light brown; while coloured diamonds are commonly yellow, grey, pink, etc.
GIA’s D-to-Z Scale
Colourless diamonds are usually graded according to the Gemological Institute of America’s (GIA) D-to-Z Scale, which ranges from D (colourless and clear, starting from the first letter of “diamond”) to Z (yellow).
Coloured Diamonds
Coloured diamonds are extremely rare and vibrant in saturation, ranging from pink, blue, green, and yellow to an exceedingly rare red. Therefore, GIA’s D-to-Z Scale is not applicable to coloured diamonds.
Cut
Cut refers to the proportions of the diamond, which are determined by the skill of the craftsman when cutting the stone. According to the rules of geometry, a perfectly cut diamond should reflect light internally in such a way that all light is concentrated on the crown of the stone, which gives it brightness and flashes of colour. In an over-finished or under-finished stone, light leaves through the pavilion, leaving the diamond dark and unattractive. Therefore, the better the cut, the higher the value of the diamond.
3%
Ideal Cut
Only 3% of top diamonds are in this grade. Almost all light that enters the diamond is reflected, representing an elegant and outstanding cut.
15%
Very Good Cut
About 15% of diamonds fall into this grade.The diamond is of very good cut and can reflect a good amount of light but is in a slightly lower price range.
25%
Good Cut
About 25% of diamonds fall into this grade.The diamond reflects most light that enters.
35%
Fair Cut
Roughly 35% of diamonds fall into this grade.The diamond is still of decent quality, but the cut is average, and the amount of light reflected falls short of the “Good” grade.
×
Poor Cut
Diamonds of this grade do not reach average industry standards. The diamond is cut either too narrow or too wide, thus it loses light through the sides or the bottom.
Choosing Your Diamond
Carat
What are the different carat grades?
Carat is the unit used to measure the weight of a diamond. 1 carat is equal to 100 points (0.5 carat is 50 points) and is equivalent to 0.2 grams. Round diamonds are commonly 0.3, 0.5, or 1 Carat in weight. Then does a 60-point diamond look twice as big as a 30-point diamond, or is the table of a 2-carat diamond twice as big as that of a 1-carat diamond? The answer is no. As diamonds are 3-dimensional, as weight increases, the diameter of a diamond does not increase by the same ratio. Weight is not the only factor that contributes to the value of a diamond. Other factors such as cut, clarity, and colour are also needed to be taken into consideration.
Choosing the right carat
- Most people are willing to spend one to two months of salary for a diamond as a gift or investment.
- Setting budget is important. If a diamond is out of your budget, you can always adjust your requirement on carat, colour, clarity or cut.
- The body shape of the wearer, such as ring size and ear shape, might affect the look and feel of the diamond jewellery. Choose a size that is suitable for the wearer is the key.
- Diamonds of the same size can look totally different on different jewellery settings. Searching diamond and its pairing jewellery design at the same time is suggested.
Key facts
- Huge diamonds are rare. The value of diamonds can increase geometrically as the weight of diamonds increases. Therefore, the price of a 2-carat diamond is not twice that of a 1-carat diamond, but even more.
- Tiny loose stones (0.08-carat or under) are much cheaper. However, the cost of mounting these stones would be higher. Therefore, jewelleries using loose stones might not be cheaper than those using one single diamond of the same total carat weight.
- Are diamonds the bigger the better? If the table of a diamond is disproportionately wider than its pavilion, the internal light reflection would be distracted and leads to poor light performance. Therefore, choosing a good cut is as important as choosing the right carat weight.
Clarity
What is clarity?
Grades of clarity can only be identified under a 10-power (10X) magnification. Imperfections on the surface of a diamond are called blemishes, while internal irregularities are known as inclusions. The quantity, positioning, size and distinctiveness of these imperfections are criteria by which grades of clarity are defined.
Determining the clarity grade
Step 1: Consider the diamond in a whole and set an initial clarity grade.
Step 2: Divide the diamond into different parts for inspection, and check the upper, lower, left, right quarters in turn.
Step 3: Carefully consider each facet - the crown, pavilion, and girdle.
Step 4: Finally, revisit the previous steps and re-consider your first impression of the diamond’s clarity.
Step 5: Determine the clarity grade of the diamond.
Key facts
Diamonds are minerals form underground; therefore, a finished diamond still has the blemishes and inclusions it naturally contains before it was mined. Gem-quality diamonds make up less than 10% of all stones mined. Diamonds of the grade VS and above are exceedingly rare. There are no two stones that are identical to one another. Therefore, the unique blemishes and inclusions of each diamond are a safe way of identifying individual stones and provide a fair and professional standard by which a diamond’s clarity grade is judged.
Colour
What are the different colour grades?
Colourless diamonds are graded from DEFGHIJ to XYZ. D, E and F grades are the most sought after, however, completely colourless diamonds are extremely rare. In most cases, G to J grades is more realistically attainable for most customers. Although only skilled graders can tell the difference between the top colour grades in finished and mounted diamonds, the price could differ significantly even between F and G grade diamonds. The best approach is to be pragmatic towards picking the colour grade that suits your preferences in both style and price.
Determining the colour grade
The larger the diamond, the much obvious the tint might be. If a diamond needed to be professionally graded, the following criteria are essential:
- A master stone for comparison
•It should be round and brilliant, and emits no fluorescence when exposed to ultraviolet radiation.
•It should be between 0.3 to 0.4 carat in weight.
•It should be of “Good” cut or above, and of clarity grade SI1 or above.
•3 to 5 master stones of a range of known colours should be used in the grading process.
- Diamonds need to be graded under diamondlite.
- Diamonds must be examined against a pure white background.
- Multiple angles of observation is needed.
- Graders must be focused on the task.
- It is common and acceptable for two people judgment of a diamond to differ by one colour grade.
Cut
What is cut?
A perfectly cut diamond should concentrate all light that enters the stone and reflect brightness and fire from the table and crown facets. If the pavilion is cut too deep, the light might not be able to refract internally and will be lost; if the pavilion is cut too shallow, light leaks through the bottom once it enters. In both cases, the brilliance of the diamond is not truly reflected. If you investigate the face of a diamond cut too shallow, you will see a fish-eye effect, while you will see a nail head effect when looking into a diamond cut too deep.
It should be noted that a diamond’s outer shape is not a factor used to determine the quality of the stone cut. Before a craftsman begins to cut a stone, he analyses the stone and decides the best way to cut it to retain the most carat weight but at the same time maximize its brilliance - this is known as fancy shapes. The most common shape in the market is round brilliants.
Some common cuts include Heart, Emerald, Marquise, Pear, and Princess.
Princess
Emerald
Oval
Pear
Heart
Marquise
Grading the cut
The best cut shows off a diamond’s brightness and fire. A diamond’s brilliance is mostly produced by the crown facets, and an Ideal Cut best showcases the skill of the craftsman and beauty of the stone.
The cut is the only factor contributing to a diamond’s beauty that can be controlled by the craftsman. The size, proportion, symmetry and polish of the cut, in addition to the different angles of the cut, give the diamond brilliance, dispersion and scintillation. The Ideal Cut brings out these three qualities in a diamond.
Diamond Certification
The diamond industry has developed an internationally recognised and standardised benchmarking system. Any given diamond certificate is approved by three examination bodies, who objectively assess the attributes of the diamond under examination. A credible certificate records the observable characteristics of a diamond, for instance the shape, weight, cut, colour, clarity, polish, symmetry, etc., to determine the grade of the purchased diamond.
Currently, the more well-known and commonly used diamond certificates include:
HRD Certiticate
Hoge Raad voor Diamond
National Gemston Testing Centre
IGI Certificate
International Gemological Institute
GIA Certiticate
Gemological Institute of America
The Leo Diamond has partnered up with IGI to create the “Leo Diamond Certificate”, which is uniquely designed and first of its kind in the Asian region. In addition to showcasing the excellence of Leo diamonds, this independent certification further guarantees the quality of Leo’s diamonds.
Description
Proof that the stone is a natural diamond.
Shape and Cut
Proof that the stone is a natural diamond.
Weight
The weight of the diamond as measured in Carat.
Measurements
Refers to the diameter of the diamond’s widest circumference, its smallest diameter and its depth (i.e. height).
Clarity Grade
The clarity of a diamond is determined by the size, quantity, colour, positioning and other characteristics of internal inclusions and other imperfections. The six clarity grades range from FL, IF, VVS, VS, SI and I.
Color Grade
Refers to the natural colour of the diamond, and is classified into several grades, the highest being D, followed by E, F, … to Z. The closer to colourless a diamond is, the higher its value. Coloured diamonds are graded according to a different system.
Fluorescence
When exposed to ultraviolet light, some diamonds emit a visible glow, usually blue in colour. The strength of fluorescence is classified into the following grades: None, Faint, Medium, Strong or Very Strong.
Polish、Symmetry、Proportion
Together, these factors determine the quality of a diamond’s cut, ranging from Excellent, Very Good, Good, Fair to Poor.
Table Diameter、Crown Height、Pavilion Depth
These factors’ relative ratios are used to judge a diamond’s proportion, which is one factor that determines the quality of the cut.
Culet Size
The culet is the area at the bottom of the pavilion of a diamond. Pointed (as in no culet) to medium-sized culets are ideal.
Girdle Thickness
The culet is the area at the bottom of the pavilion of a diamond. Pointed (as in no culet) to medium-sized culets are ideal.
Plot of Internal and External Inclusions
Both internal and external inclusions can be plotted on cross-sections of a diamond’s top face and bottom, so that their size and positioning can be recorded.
Diamond Settings
The appearance of a diamond, such as its size, shape and colour, is affected by the way the stone is set. Therefore, it is imperative to pick a setting that best suits the wearer’s preferences.
Prong Setting
U-Shaped
For engagement rings, the prong setting is by far the most popular. A thicker shank and a U-shaped prong will make the diamond look bigger. The elegant look suits professionals and mature ladies.
Meanwhile, a thinner shank together with a three- or four-claw prong will lend the ring a more minimalist look, and is suitable for younger women.
Tension Setting
The tension setting holds the diamond in place by the pressure of the metal band. The diamond is set in small grooves cut into the sides of the shank, which gives the ring a fluid and clean appearance. The setting also allows light to enter the diamond more fully, giving it a brilliant finish.
Product Care
Taking Care of Diamonds and Gemstones
Here are a few suggestions to protect and maintain the beauty of your gemstones:
- Avoid collision and abrasion: Even though diamonds are less susceptible to damage than more delicate gemstones, it is ideal to avoid collision with hard surfaces and abrasion. Handle gemstone accessories carefully to avoid chips or loss in shine. One should also check regularly if the gemstone is firmly mounted so any loosening can be dealt with swiftly.
- Avoid high temperatures and contact with chemicals: Many mounted gemstones lose their colour when exposed to high temperatures or to sunlight for long periods of time. Contact with acidic or alkaline chemicals can also lead to a loss in colour, or worse, erosion and dissolution of the stone.
- Regular cleaning: Dust and oils can build up in accessories and reduce their shine. Accessories must be cleaned and conditioned regularly when they are not worn.
Cleaning method: Prepare a bowl of warm water and add a few drops of neutral detergent. Dab a cotton bud or a small brush in the water, then gently cleanse the accessory. Leave it to dry in a well-ventilated area and its shine will be restored.
- Wear and store with care: When doing sports, showering or doing household chores, it is best to remove jewellery to avoid damage. When not wearing accessories, store them properly in a jewellery box. In storage, accessories should face upwards, and one should avoid keeping too many in one box to avoid abrasion and scratching.
Taking Care of Silver
Here are a few suggestions to protect and maintain the beauty of your silver accessories:
- Avoid direct contact with soap, cosmetics, perfume and skincare products, as these chemicals will dull the surface shine. Pool water and sea water will have a similar effect. Silver should be dried immediately after contact with water.
- Avoid direct contact with soap, cosmetics, perfume and skincare products, as these chemicals will dull the surface shine. Pool water and sea water will have a similar effect. Silver should be dried immediately after contact with water.
- Silver accessories should be stored independently in pouches or separately in a jewellery box to avoid scratches or damage from abrasion. Exposure to air should also be avoided to prevent oxidation.
- Silver is a very stable element, however, it does react to sulphur in the air, which produces black spots, therefore contact should be minimised.
Taking Care of Pearls
Pearls do lose their shine over time, and can yellow from contamination by grease and oils. Therefore proper care is indispensable. Here are a few suggestions to protect and maintain the beauty of pearls:
- Pearls are delicate, and abrasion with rough materials should be avoided.
- Pearls should not be in contact with sweat, vinegar or any acidic substances, as it will lead to erosion.
- Contact with perfume and hairspray should be avoided, as these chemicals can be easily absorbed by pearls and reduce their shine. Pearls should be worn only after cosmetics are applied.
- To maintain shine, pearls should be washed with water and cleaned with a soft towel, then left to dry in a well-ventilated area before storing properly.
