The date of the report is the date when analyses are completed and when the report is issued.

Unique reference number

The Laboratoire Français de Gemmologie gives a unique reference number to each item submitted for examination. This number identifies the item at each stage of analysis. When a stone has already been seen and comes back after a re-cutting or a preliminary examination, a new number is assigned to it.

Shape, cut and dimensions

The shape, cut and dimensions describe the external appearance of the stone. When you submit a piece of jewellery with several stones, or lots, we indicate the diametrical variation of the lot.


The weight (mass) of the stone is shown in carat weight with a precision of two decimals. The third 9 after the decimal point is rounded up to the nearest hundredth. For instance: 0.9990 will be shown as 1.00 carat, 0.9989 shown as 0.99 carat. If it is a jewel set with stones, then it is weighed in grams.


The colour of a diamond is determined by comparing it to our diamond masterstone set. The colour grade is referenced in the following scale (you will find the same grading scale in your reports):


The inclusions found in your diamond determine clarity. We use the following scale in compliance with CIBJO rules (you will find the same grading scale in your reports):

Cut Grade

The cut grade is based on strict standards combining information on proportions, symmetry, polish and thickness of the girdle. The cut grades range from: Excellent – Very good – Good – Fair – Poor.

Poli & symmetry

The Polish / symmetry grades range from : Excellent – Very good – Good – Fair – Poor. They are essential to cut grading.


The fluorescence grades range from : None – Faint – Medium – Strong – Very strong.


It is in the comments section that the LFG provides additional information related to treatments. For example the HP-HT treatment of your stone, or laser drilling.

(+33) 01 40 26 25 45
30, rue de la Victoire - 75009 Paris
Monday - Thusday : 9H30 to 17H00
Friday : 9h30 to 16h30
Withdrawal files at same days and time


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