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Comprehensive grading
 system that explains the 17 diamond
 grading parameters
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SRK Grading System (SGS)
Pure Transparency
SGS is a metric derived over a transparent 17-step process to authenticate the true
value of a diamond. The system is so refined that objectivity truly wins over
subjectivity. In a sense, the SGS metric is an authoritative and conclusive measure of
a diamond, going beyond the current industry standards of 4C evaluation.
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Diamond Shape
Shape is an important factor to consider when buying diamonds.
From princess cut, pear or oval shaped diamonds to heart, cushion,
marquise shape and emerald, every shape manufactured by SRK has its own attributes.
Pricing parameters followed by the SGS:
Size range
Clarity is a term used for describing the number and size of inclusions in a diamond. Inclusions are mainly traces of non-crystallized carbon that may appear on the diamonds internally or externally. A flawless diamond contains no inclusion and is considered extremely rare and valuable. Large inclusions affect the brilliance of the stone as they interfere with the dispersion of light. 

We grade diamonds on the basis of purity by determining following categories:
Additional comments for certified stones. 

- If our (SGS) Clarity grading is VS-2 and laboratory gives us SI-1 certificate, we have to specify the exclusive clarity in the comment column.
- If our (SGS) clarity grading is SI-1 and the laboratory gives us a VS-2 certificate, we have to specify the upgraded clarity in the comment column.
Diamonds close to being colorless are more rare and valuable. Diamonds that display little color allow more light to pass through, resulting in a burst of brilliance. On the basis of color, diamonds are allocated a grade, starting with D grade (for colorless diamonds) and ending in a Z+ grade. Some diamonds are also found in vivid colors such as red, blue and pink.
SGS Color Grades
Additional comment for Certified stones.

- If our (SGS) color grading is G and the laboratory gives us H certificate, we have to specify exclusive color in the comment column. 
- If our (SGS) color grading is H and the laboratory gives us G certificate, we have to specify upgraded color in the comment column.
Cut gives a unique sparkle and brilliance to diamonds. Cut quality depends on the craftsmanship of the diamond cutter. If a diamond has perfect color and clarity but the cut is poor, it will lose its brilliance. 

We grade diamonds on the basis of cut by determining following categories:
SGS Cut Grades
Polish mainly describes the smoothness of the facets in a diamond. This is the last step in the diamond cutting procedure. Brilliance of a diamond can be enhanced with a smooth polishing of the facets. 

Diamonds are graded on the basis of polish by determining following categories:
SGS Polish Grades
Symmetry refers to the alignment of the facets (surface conditions) in a diamond. Each facet needs to be of a consistent size and positioned opposite the corresponding facet. Poor symmetry misdirects the light that enters the diamond. 

We grade diamonds on the basis of symmetry by determining the following categories:
SGS Symmetry Grades
Heart & Arrows
An impeccable round diamond with perfect angles is called ‘Heart and Arrows’ (H&A). These diamonds are graded with extra specifications under SGS. They are not included in the regular cut criteria as H&A diamonds are considered better than the most excellent cut diamonds.
SGS H&A Grades
Luster and brilliance are two most valued attributes of a diamond. Luster describes a diamond’s fire and sparkle. Depending upon the light reflected from the stone, SGS grades diamonds on the basis of two levels of luster: 

Level of Brilliance:
SGS Luster Grades
Level of Milkiness:

Milkiness is mainly a hazy inclusion in the diamond that appears white or grey in color. This haziness affects the brilliance of a diamond. 

Such diamonds are further classified based on the magnitude of milkiness.
SGS Milky Grades
When exposed to ultraviolet radiations, a diamond glows if it carries the characteristic of fluorescence. Black light is the most common source of UV exposure in which many diamonds give off a glowing blue coloration. 

SGS grades diamonds based on the level of fluorescence present in them:
SGS Fluorescence
Grades Description
Black Inclusion (Natts)
As compared to the total inclusions, we grade diamonds on the basis of black inclusions by determining the following categories: 

We grade diamonds on the basis of black inclusions as compared to the total inclusions by determining the following categories:
SGS Black Inclusion
We specify two kinds of black inclusions 
Table Black Inclusion
Side Black Inclusion
Other Inclusion
Diamonds at SRK are graded on the basis of five types of Inclusions. Pin Points (PP), Clouds (CLD), Crystals (CRL), Feathers (FR) and Spreaded (SPR).
Pin Point (PP): It is a small crystal that looks like a tiny dot when using a 10x loupe. Generally, pin points are white in color; however, they can also be found in a dark color.
Clouds (CLD) :This consists of various tightly grouped pin points. Some are quite dense (impossible to see with the naked eye) whereas others look like a light haze.
Crystal (CRL):It is a mineral crystal contained in some diamonds. Crystals can appear alone or in groups and they can be of any size and color.
Feather (FR):This is a general term used for any break in the diamond.
Spreaded (SPR):This appears when the feather inclusions are in a greater number. They are spread across and not grouped together.
SGS Other Inclusion
We specify two part of other inclusions

• Table other inclusion
• Side other inclusion
Open Inclusion
Open inclusion is the inclusion on the surface of a diamond. Under SGS, diamonds with open inclusions are graded as mentioned below:
SGS Open Inclusion
We specify two part of open inclusion

• Table open inclusion
• Side open inclusion
Extra Facet
It is an extra facet that is placed on a diamond’s normal facet without considering the symmetry of the stone. These are additional to the facets required for making a brilliant cut diamond.
SGS Extra Facet Grade
Here’s an extra specification for the internal graining in the comment column: 

• Slight Internal Graining
• Heavy Internal Graining
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Pure Relationships
Pure Origin
Pure Alliances