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Loose Diamonds Tutorial

The International Diamond Grading System. Updated 4 Sept 2023

Loose Diamonds grading system which determines the nature and  quality of diamonds is accepted as the international diamond grading standard now. The system involves procedures that grade the quality of the loose diamonds by detecting evidence of stimulants, synthetics and other known forms of treatments. The grade certificate determines the grade and quality of a diamond

Diamonds actual size
Actual diamond sizes compared to fingers
To figure it out is best to measure rings at any Jewlery shop

The 4 C's

Cut- the cut of a diamond is one of the major Cs that makes it so precious. It brings out the sparkle, brilliance and fire of a diamond. A perfect cut diamond will possess flawless proportions and finish rendering the precious stone its sparkling quality and appeal. The cut of a particular diamond depends on 3 factors. The brilliance which refers to the total amount of light reflected by the diamond; fire referring to the distribution of light into the spectrum colors and scintillation referring to the pattern of light and dark, flashes of light during the movement of a diamond. Cut is graded on a scale from Excellent to Poor and is mostly applied to Round Brilliant Cut Standard diamonds in the D-Z color range.

Clarity- clarity is another quality that makes diamond so valuable.It actually refers to marks on a diamond which is an obvious result of its origin deep within the earth. The inclusions (internal) and blemishes (external) are quite common in loose diamonds and their absence is marked on a clarity scale from flawless (FL) to obvious inclusions (I3). The standard clarity scale comprises 12 grades. Other than blemishes and inclusions, relief, nature, position and size is also considered under 10×magnification.

Color- the quality of color in a diamond is hailed for its inconspicuousness. The less the color of a diamond, the more is the value. Most of the original loose diamonds range from being colorless to having sober hints of brown or yellow. The standard color grade marks a diamond on a scale of D (colorless) to Z (with tinges of yellow or brown) when compared with stones of familiar colors. Each letter grade represents a range of color and the procedure is performed under controlled lighting and specific viewing conditions. Diamonds with colors blue, pink are beyond the grade “Z” and are considered as Fancy colors.

Carat Weight- diamond is measured in the industry using a metric carat scale where 1 carat = 0.2 grams which is similar to the weight of a paperclip. A highly accurate electronic scale is used to measure the carat weight of a diamond which is rounded to the nearest 100th of a carat. The majority of loose diamonds used in intricately designed jewelries measure1 carat. 2 loose diamonds having the same weight can have different values depending on color, clarity, cut and therefore precision is vital.


Proportions refer to the facet angles, dimensions of a polished diamond and the relationship between them. In fact, the appearance and quality of a diamond depends on the inter relationship of the proportions. We report measurement of 8 proportions for round brilliant cut diamond, while for fancy shape loose diamonds that are outside the standard grades,we measure values for table size and total depth. Moreover, features like culet size and girdle thickness are accounted with word descriptions based on visual estimation. 


Finish involves all the characteristics of craftsmanship. The polish and symmetry talk about the finish of a diamond where polish includes the overall condition along with the smoothness of the diamond surface and symmetry includes placement and alignment of the facets, shape and outline of the stone. These characteristics are visually evaluated and rated on the scale ranging from Excellent to Poor.


Fluorescence refers to light emanation from a diamond when held against ultraviolet radiation. Fluorescenceis a description, the strength of which is illustrated as: None, Faint, Medium,Strong and Very Strong. The color of the fluorescence is noted in case of medium, strong and very strong. 

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Diamond Anatomy 

                          Diamond's part names diagram, Table, Girdle, Culet, Pavillion

                           Diamond's proportion characters diagram, depth, table, Pavilion, crown, girdle



Diamond Clarity Chart

Very very Slightly Included',very difficult to see inclusions under 10% magnification


                                            FL-Flawless  IF-Internally Flawless




Very Slightly included inclusions
are not typically visible to unaided eye
less expensive then the VVS1 or VVS2




                                                        Slightly included inclusions.are visible under 10x magnification SI2 may be visible to the naked eye.SI3 is graded by EGL only and

 defined as the border line between SI2 and I1. It is not eye clean but not as obvious as I1




                                                       included: visible to the naked eye,but still will have sparkle and brilliance. The perfect choice for the tight budget






Diamond color scale illustration diagrams, D to Z

The Diamonds Color Scale From C to Z

Main Diamond Shapes

Most Popular Diamond Shapes



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