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Jewelry, Gems, & Minerals/Class 1 or class 2?


Dear Jonathon,
I understand that a diamond can be categorized as class 1, class 2, class 3, or class 4 depending on measurements like the size of the table, the total depth, the girdle thickness, etc. So what if my diamond measurements mostly belong to class 1, but 2 to 3 of the measurements belong to class 2?

For example, crown angle for class 1 is 34%-35% while mine is 33.5%. Girdle thickness 0.7%-2.7% while mine is 3%. Every other measurements are within class 1 diamond. My diamond is triple excellent.

Is my diamond class 1 or class 2?

Hi Choo,
I think you are referring  to the diamond cut grading system and the classification of your diamond will vary with which gem lab grades your diamond (American gemological society AGS, Gemological Institute of America GIA) and what cut your diamond is (heart, princess, pear etc) For example, GIA graded diamonds, this is the grading system followed for round brilliant cut diamonds But also please bear in mind that the other 'C's' are also important in diamond grading (clarity, Color, carat) You can find more information on that here


Jewelry, Gems, & Minerals

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Jonathon Ohayon


Any diamond, jewelry or engagement ring related questions. I am a Graduate Gemologist and have extensive experience in the field of Gemology including diamonds, gemstones, and precious metals.


I have been working in the jewelry industry for over 10 years and am a Gemologist. I also appraise diamonds and jewelry for

Graduate Gemologist and Bachelors in Business Management. Apprenticed under Head Gemologist of for 2 years.

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