Diamond Grading System

Across global markets, diamond pieces are always quoted in rate per carat. The usual industry practice is to quote weights up to the 2nd decimal digit only. Yet, since we believe in total precision for our customers, we quote weights up to the 3rd decimal digit. The price difference, after factoring in the 3rd decimal digit of a cent, is justifiably accurate. 3rd digit quote eliminates the possibility of unnecessary rounding off of any fraction.

The Above Table indicates the price difference between clarity grades while other parameters remaining constant. The prices are subjected to individual grade & market trends.

The Above Table: Indicates the price difference between table inclusion grades while other parameters remaining constant. The prices are subjected to individual grade & market trends.

Clarity- Black Inclusion

Black Inclusion(s) are natural inclusion(s) trapped in a diamond during its formation in the earth’s crust & appear black in colour. As the presence of the black inclusion(s) in a diamond has an impact on the price of the final stone, we have introduced the grade to try to precisely indicate the degree of black inclusion(s) & their relative effect on the stone appearance & their value. These inclusion(s) are generally referred to as ‘Natts’.


The DGS NO indicates almost no black inclusion(s) in the diamond, N1, N2 & N3 indicate diamonds with increasing proportion on black inclusion(s) compared to total inclusion(s). AndN4 denotes that most of the inclusion(s) in the diamonds are Black.

Again, each of the 5 sub-grades i.e. from N0 to N4 directly impacts the pricing of a diamond, which is explained in the table below:

The Above Table indicates the price difference between Black inclusion grades while other parameters remaining constant. The prices are subjected to individual grade & market trends.

Clarity - Inclusion Pattern

The indicates how densely the inclusion(s) are located within the diamond, i.e. whether they are Concentrated or Scattered.

In DGS Inclusion Pattern grades are as follows
S1: Scattered
S2: Semi Scattered
C1: Light Concentrated
C2: Semi Concentrated
C3: Most Concentrated

This again is unique to the DGS & each of the 5 sub-grades i.e. from S1 to C3 directly impacts the pricing of a diamond, which is explained in the table below:

G3: Heavy Internal Graining

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.



Clarity - Internal Graining

These are naturally occurring lines, at times even clustered together indicating irregular growth of the diamond crystal during its formation. These line like structures, usually transparent & invisible to the naked eye, affect the clarity & hence the price of diamonds.

In DGS Internal Graining grades are as follows

G0: No Internal Graining
G1: Light Internal Graining
G2: Medium Internal Graining

Each of the 4 subgrades i.e. from G0 to G3 directly impacts the pricing of a diamond & are not normally considered by other grading standards, the same is explained in the table underneath:

Internal Graining Type

In internal Graining, there are many naturally occurring lines that have different types & colours. 

These types of colours have an impact on the clarity of a diamond, especially in IF clarity grade. Presently, we grade Internal Graining type in VS2- & above clarity grades.

In DGS Internal Graining types are as follows:-

Transparent     Tra

Whitish             Wht

Brownish          Brn

Cubical Cub

Reflective Ref

Green Grn

Grain Centre GrCnt

 
(Source: IGR London)

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Clarity- Opens

Opens ( a surface characteristic) especially large ones, can noticeably affect the price of a diamond when an inclusion(s) or a feather within a diamond is open near the surface, or if there is a chip, knot, cavity, pit, nick or natural on the surface, such flaws are graded as ‘Opens’

In DGS Opens grades are as follows

NN: No Open

VN: Very Small Open 

SM: Small Open

MD: Medium Open

LG: Large Open

Additionally, to easily locate OPens in diamonds, the following is specifies.

1) TOP indicates Opens in the Table,

2) COP indicates Opens in the Crown,

3) GCOP indicates Opens in Gridle towards the crown

4) POP indicates Opens in the Pavilion

Each of the subgrade i.e. from NN to LG directly impacts the pricing of the diamond which is not normally considered by other grading standards, the same is explained in the table below:

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Luster

Luster is the quality & quantity of light reflected from the surface of a diamond. This is often referred to as brilliance, sparkle or fire. Luster plays a key role in the diamond buying decision as it is one of the most important elements which gives each individual stone its particular appeal.

In DGS Luster grades are as follows
EX: Excellent
VG: Very Good

GD: Good

FR: Fair

Besides some diamonds may have a little whiteness or cloudiness present in them, which are known as milky luster diamonds. Such diamonds are further classified into subcategories depending on the extent of the milky effect, using the below terminologies; 

ML1: Very Slightly 

ML2: Medium Milky

ML3: Heavy Milky

ML4: Strong Milky

(Source GIA)

All these subgrades directly impact the pricing of the diamond which is not normally considered by another grading standard, the same is explained in the table below:

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Colour

Colour is a defining factor while valuing diamonds. It can range from colourless to yellow, brown, etc.- the more colourless a diamond, the greater its rarity & value.

Conventional grading system usually covers only 17 colour grade, but to provide in-depth information on the colour, DGS provides a total of 32 colour grades from D to R with the addition of ‘better(+)’ & ‘lower (-)’ grades between the standard colour grade ( For Example:- G+, G & G-).

In addition to grading the colour of diamonds other factors such as the Shade/Hue, inherent Fluorescence in a diamond, as also its colour, are factors that can have an influence on the overall colour of the diamond & are therefore critical to the grading too.

 (Source: GIA)

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Colour Shade (Hue)

At times, in a diamond crystal along with Carbon atoms Nitrogen or Boron atoms also form bonds that give rise to ‘ colour centres’, which radiate a deeper shade across the diamond, giving it a Hue or Tone.

Consequently, to simplify our customers understanding of ‘shade’, also know s ‘hue’, we grade a total of 44 shades. 18 of these which are most commonly graded by us are enlisted below: 

WH: White                                        PL: Purple
OWH: Off White PLP: Purplish Pink

YL: Yellow PN: Pink

BR: Brown PNB: Pinkish Brown
GNY: Greenish Yellow PNP: Pinkish Purple

BLKGR: Blackish Grey YLB: Yellowish Brown

BPLP: Brownish Purplish Pink

BPNP: Brownish Pinkish Purple

BRP: Brownish Pink

FP: Faint Pink
GBK: Greyish Black

GR: Grey

Eg: YLB- Yellow Brown indicted brownstone has a yellow tinch.
All these sub-grades have an impact on the pricing, which is explained in the table below: 

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Fancy Colour 

“Fancy Colour Diamonds” are graded using the depth or intensity of colour increasing from top to bottom. Diamond exhibiting colour outside the normal colour range is referred to as fancy colour diamonds. The combined effect of Hue, Tone & saturation leads to the colour appearance of the diamond.

Hue: is a basic impression of colour, the components that give colour & its identity
 

Tone: is the relative amount of lightness or darkness in the colour

Saturation: is the strength, purity or intensity of hue

For fancy colours:

In light shades (for example Pink, Blue, etc) we start grading from faint (FT) colour.

In all other Dark Shades (for example Brownish Yellow, Brownish Greenish Yellow, etc.)we start grading from very light (VL) colour.

In the yellow shade, we start grading from Fancy Light(LT) colour.

DGS for fancy colour stones:

FT: Faint

VL: Very Light
LT: Fancy Light

FN: Fancy Low

FN+: Fancy High

IN: Fancy Intense Low

IN: Fancy Intense

IN+: Fancy Intense High

VD: Fancy Vivid Low

VD: Fancy Vivid


Fluorescence
Fluorescence is the emission of light by a diamond when exposed to ultraviolet radiation.

Generally, as per the industry practice, the Fluorescence grades are usually from FL0 to FL4 with broad ranges. For more accuracy, we provide the addition of  ‘better (+)’ & ‘lower (-)’ in FL1 & FL2  & further we grade better (+) in FL3, making it easy to understand.

In DGS Fluorescence, grades are as follows
FL0- Name

FL1- Faint

FL2-Medium

FL3- Strong

FL4-Very Strong Fluorescence

(

Fluorescence Colour
Depending on the molecular structure of carbon atoms in a diamond, Fluorescence can have different colours.

Fluorescence colour like white, blue, yellow, orange & green has a direct impact on the overall colour.

Cut

Out of the 4C’, this is the only one that is not created by nature, but instead is the creation of skilled and experienced craftsmen. Cut determines how well a diamond will reflect light, leading to its scintillation or brilliance, which is the essence of a beautiful diamond. 

The cut or the “make” of a diamond refers to the angles and proportions as a combination of all facets created when transforming a rough diamond into a polished one. 

In most cases, Cut grades are provided only for round shapes even by external labs. In fancy shapes, it is technically difficult to identify, cut and grade the stones. With extensive and rigorous research, We are providing cut grades for different fancy shapes diamonds in addition to round shape diamonds. 

The DGS grades 11 Cut grades and all these impact the pricing, which is explained in the table underneath:

ID Ideal

EX Excellent

VG Very Good

GD Good

FR Fair

Further, we also provide ‘better (+)’ and ‘lower (-)’ grades from EX to GD which makes the cut grade more detailed and accurate.

(Source: GIA)

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Cut-Polish

Polish is the overall condition i.e. the sheen or shine of a finished diamond’s facets surface. The precision in polishing gives more finish to a diamond and invariably the best reflection of light from the surface of a Diamond. Venus Jewel is known for its Ideal and Excellent finishing.

In DGS Polished grades are as follows:

ID Ideal

EX Excellent

VG Very Good

GD Good

 (Source:GIA)

Each of the above 4 sub-grades directly impacts the pricing of a diamond, which is explained in the table below:

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Cut- Symmetry

Symmetry refers to the exactness of the shape & arrangement of facets, their deviation & angles. 

Better symmetry clearly indicates that a diamond has been manufactured not only with the utmost care but also with a high level of perfection & accuracy. The better the symmetry, the better the brilliance & the resulting appeal of the diamond.

This is done through:
1) Extensive research by a team of Artistas/ Quality controllers/ Technocrats
2) Arithmetic & trigonometric parameter controls

3) Algorithms/ reports developed in house
4) Resulting in Distinct product quality & enhanced beauty 

In DGS symmetry grades are as follows
ID- Ideal

EX- Excellent
VG- Very Good

GD- Good

 
(Source: Delmas Diamonds)

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.

Cut Spread Ratio

We consider ‘Spread’ as a crucial factor in grading diamonds. The term ‘Spread’ is an industry term that refers to a diamond’s face-up size compared to its weight. One can also call this ‘weight ratio’ or ‘millimetre footprint versus weight’. Currently, we grade Spread Ratio for round shape diamonds only. 

Theoretically, a standard or ideal Round Brilliant would have proportion such that a 1.00 Ct stone would have a diameter of 6.47 mm. On comparing any other diamond with this ‘Ideal’ diamond, if it has zero or no spread, then this diamond would be equal in size, weight and proportions to the Ideal diamond. 

In other words, for a given diameter negative spread indicates diamond weight (in % terms) being in excess of what it ideally should be, whereas in the reverse case, positive spread indicates diamond weight being less than the ideal. Spread considers overall weight and diameter, so one need not remember the parameters like Girdle, Depth and Crown Height. If there is excess or reduced weight this is reflected in the spread, making it a logical parameter for purchasing diamonds. 

However, spread as a factor in purchasing diamonds functions as a precise indicator of whether a given diamond is actually justifying the price being asked. In other words, to a customer, the spread can clearly identify whether, for a given price, a diamond is carrying more weight than it ideally should or less. 

Cut- Culet

The bottom-most point or vertex of a diamond, where all the pavilion mains meet is termed as the culet. If all pavilion mains do not meet at this point, or if the culet is chipped or broken, it is termed as open, in which case, it would resemble a minuscule facet, octagonal in shape, like the table. 

The DGS Culet grades are as follows
NN: Pointed
VS: Very Small

SM: Small

MD: Medium

 
(Source: GIA)

The Above Table, indicates the price difference between Inclusion pattern grades while other parameters remaining constant. The Prices are subjected to individual grade & market trend.