Diamond weight (Carats) Carat is a unit of weight used for gemstones. This word come from ancient Greek “Keratia” that means horns and refers to the famous carobs tree the beans of which were used as a standard weight With time the word changed in the Italian language to carato, to qîrât (little bean) in the Arabic language. The measure for the kerátion weight is equal to ….

The weight for a diamond or a gemstone is in CARAT, often abbreviated to “CT”. One carat is equal to 200 milligrams, 5 carats is equal to 1.00 gram.

1 carat is divided into 100 parts, called “points”. Therefore a 25 points diamond weighs ¼ or 0.25 carat, and a 50 points diamonds weighs ½ or 0.50ct.

The weight for a diamond or a gemstone is usually expressed in carats and decimals. For example a 1.09 ct gemstone, is “1 carat zero nine”. A diamond that weighs 0.99ct is a “ninety nine points”.

Diamond Clarity

The clarity of a diamond determined by the number of visible inclusions in the stone when examined though its table and its size, its contrast and its position when examined through its crown using specialist microscope of x10.

Like the colour the clarity is an important factor to determine the value of a diamond. It is very rare for a diamond to be absolutely perfect. Diamonds have internal characteristics called “inclusions”, and some external irregularities called “flaws”.

Sometimes, during its formation, a diamond can contain some others crystals or minerals. Depending where they are located in the diamond, those crystals or minerals can still be there after the cut or the polish.

The clarity grade is determined by the lack of flaws or inclusions.

Some clarity characteristics may have some negative influence on the diamond value, but they are very useful sometimes to find out if it’s a natural diamond, a synthetic or an imitation.

(FL) Flawless: No internal and external flaws under a x10 magnification.

(IF) Internal Flawless: No internal inclusions. May have some very small flaws only visible under a x10 magnification.

(VVS) Very Very Slightly included: Divided into two sub-categories, VVS1 and VVS2, it is extremely difficult in either of those two cases to see inclusions; the most typical ones are tiny pin-points, clouds, tiny feathers or internal granules.

(VS) Very Slightly included: Divided into two sub-categories VS1 or VS2. Minor inclusions impossible to detect with the naked eye. Typical inclusions are crystals, feathers, clouds and tiny pin-points group.

(SI) Slightly Included: Divided into two sub-categories SI1 or SI2, most of the time the inclusions are located at the centre and easy to find. Sometimes an inclusion can easily be seen with the naked eye, but not obviously found when the diamond is mounted and examined in normal circumstances (on a ring, on a pendant or on earrings).The typical inclusions are crystals, feathers, clouds.

(I1) Included: Divided into three sub-categories I1, I2, and I3. The inclusions are visible with the naked eye. The typical inclusions are big crystals and feathers that, depending on their size and contrast can change the diamond brightness.

The clarity is an important part to estimate a diamond.

Diamond Colour

The colour of a diamond can be estimated in different ways, such by the colour than by the shades.

The diamond colour grade is an alphabet that starts with the letter “D” (colourless) up to the letter “Z” (yellowish).

Although diamonds currently on the market come in different shades, many buyers believe that all the diamonds are white or colourless.

Nowadays, colourless diamonds (D to F) are very expensive (regardless the clarity) and for most buyers is a high price.

Some diamonds (G to J) once mounted in jewellery seems to be colourless for a novice eye but we can see a real difference from the letter “J”.

On a colour scale from D to Z, it’s very easy to see the difference of shades between colours from K to M.

Diamond Cut

Term used to designate the shape of a stone (round, pear, oval, etc....) and the finish (the proper geometric proportions in which the diamond is cut).

The size of a stone is an essential factor to determine the brightness of the diamond regardless the shape.

Ideal cut

Round diamonds well proportioned (the depth and the table percentage that create the perfect balance for the fire and the brightness) are among the best. Very often they have the best level of polish and symmetry that indicates that the cut of the stone has been done with great care. These diamonds went through the hands of the best craftsmen who maximised their beauty.

Most of the time the ideal diamonds are more expensive than others for three reasons:

1) It took more time and talent to achieve the perfect size

2) They are high demand

3) A big part of the original rough diamond has been sacrifice to obtain the ideal proportions.

Very good cut:

Diamonds cut that respect the depth and the table proportion. Those remarkable proportions enhance the fire and the brightness of the diamond.

Good cut:

Diamonds cut that respect the proportion, acceptable but not perfect. They generally offer a good brightness and sparkle and make beautiful jewellery.

Poor cut:

Diamond cuts according to the proportion, less perfect, they have been cut to enhance the weight of the stone without taking care of the brightness and sparkling. If they are less expensive than the very good or good cut diamonds, they still don’t have the brightness and the sparkles expected for a diamond.

Fair cut:

Diamonds whose proportions and finish are fair and give an inert aspect. We don’t advice those stones for jewellery.

Depth:

The diamond height (measure between the lowest point of the colette and the table on the top of the stone)

Depth percentage:

The diamond height (measure from the colette to the table) divided by the diamond width.

The depth percentage is important to create the brightness and the fire of the stone. A too low depth percentage or too high can cause the loss of the radiance.