How to Read - WGI ™ Diamond Gemological Report - World Gemological Institute
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How to Read – WGI ™ Diamond Gemological Report

The WGI ™ Grading Report includes an assessment of the 4’cs – Colour, Clarity, Cut & Carat weight – along with a plotted diagram, its clarity characteristics and a graphic representation of the diamond proportions.


WGI™ issues a Diamond Grading Report for natural, lab-grown, clarity enhanced & colour enhanced weighting 0.10 carats or more. For Round Brilliant cut diamonds, the report also includes a cut grade report .

1. Date

– date of Diamond was examined by WGI™ Gemologist.


2. WGI™  Certificate Number

– unique number registered in WGI ™  database.


3. Shape & Cutting style

– the outline of the diamond (shape) and the pattern of the facet arrangement (cutting style).


4. Measurement

– Diamond dimensions listed as “minimum diameter “ –  “maximum diameter ” depth for round Diamonds and Length + Width +Depth for fancy – shaped diamonds.


5. Carat Weight

–  weight given in carats, one carat is equal to 1/5 (0.20) of a gram.


6. Color Grade 

–   the absence of colour ranging from colourless to yellow or any fancy colour when compared to WGI™ master colour stones. * if a colour treatment was detected it will appear in the comments.


7. Clarity Grade 

–   Graded on a scale from flawless to included based on size, nature, number , position and relief of characteristics visible under 10* magnification.


8. Cut Grade

–  for Round Brilliant Diamonds. Cut Grade incorporates the aspects of face up appearance, design and craftmanship graded on a scale from Excellent to Poor.


9. Polish 

–  Smoothness of the diamonds surface, assessed on a scale ranging from excellent to poor.


10. Symmetry

–  Exactness of the diamonds outline and the shape placement and alignment of its facets. Assessed on a scale ranging from Excellent to Poor.


11. Fluorescence  

– Strength and Colour of the diamond when viewed under long-wave ultraviolet light. A fluorescence description of none to a range of fluorescence from Indiscernible to Very Faint.


12. Inscription (s)

– Any text, symbols, logos or unique report number inscribed on the diamond’s girdle or any facet.



– Additional identifying characteristics of features that one not otherwise represented on the report. If treatment is detected such as laser drilling, fracture filling, colour treatment, it would be described here.


14. Proportion Diagram 

– Graphic profit representation of the diamonds actual proportions.


15. Clarity Plotting  

– Approximates the shape and cutting style of the diamond symbols indicate the type or nature, position and the approximate size of a clarity characteristic.


16. Image 

– In some cases WGI ™  will add the image of the stone to represent the laser inscription or a specific color.


17. WGI ™  Color scale 

– Illustrates the WGI ™  colour grades and their relative position in the WGI ™  color grading system.


18. WGI ™   Clarity scale

– Illustrates the WGI ™  clarity grades and their relative position in the WGI ™  clarity grading system.


19. Security hologram sticker

– safe guard report integrity and facilitated document authentication.


20. QR code

– A barcode when scanned , verifies date on the report against WGI ™  database.


21. Terms & Condition 

– Drafted in favour of the customer that purchases the services and recommended for use with customer purchase order.