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 Post subject: Diamond Grading course
PostPosted: Sat Jul 18, 2020 4:06 pm 
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Hi

As you can guess by my name, I am a newbie in the diamonds world!

I am starting a new business where I will be having customised jewellery made abroad for clients and it will mostly involve melee/star diamonds or the -2 sieve diamonds. I have managed to find a few suppliers in India for the diamonds and I am ordering 1 carat packs of their VS1/VS2 star diamonds as samples just to get an idea of their quality. I will show these samples to an experienced jeweller in my city who will assess their clarity/colour and the reason for this is because I am aware that a lot of wholesalers may advertise melee parcels as VS then send out 50% Vs and 50% Si, or advertise F-G colour then ship out G-H colour diamonds etc.

I have found a GIA diamond grading course in the UK which runs for 5 days and costs around $1700. It includes around 16 hours of practicals (with a practical test at the end) however the diamonds which we will be practising to grade will only be a minimum of 0.30 carats so this will be completely different to what I will need to assess (melee diamonds) however I have been told that the principles are mostly the same and I will be able to go off and grade my own melee diamonds in the future. However, I have also read online that assessing melee diamonds is an extremely difficult task even for experienced jewellers. Does anyone have any opinions about this?

I just don't want to risk paying $1700 for a course and $500 in hotel costs to learn how to grade larger size diamonds for a week, then realising that I am not better off in terms of trying to assess/grade my melee diamond packages that I will be purchasing.


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 Post subject: Re: Diamond Grading course
PostPosted: Sat Jul 18, 2020 4:56 pm 
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Well since you are new to the Diamond World I strongly suggest you take the course. Otherwise you are just stuck relying on others to confirm quality and value. What you do know will hurt you for sure. The rules of grading will apply to all sizes. That course will save you enough mistakes to be a profitable investment.

With melee in color ranges between F-H, and clarity ranges of VS1-SI2, the quality of the cut will make the biggest difference in how your finished jewelry looks.

I am not sure what you mean by "Star Cut". I know of maybe 1/2 dozen facet patterns (number of facets) that various Indian firms are marketing as star cuts. There are also firms using the term str to indicate the quality of cut. That is in addition to star shaped stones. There are also a number of cutting houses that use Star in their name. What specifically are you speaking about.


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 Post subject: Re: Diamond Grading course
PostPosted: Sat Jul 18, 2020 7:22 pm 
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It has been my experience that a -2 sieve produces stones 1.0-1.2mm.
That is very small and no one would bother to grade each stone for color and clarity.

Those stones should average about 0.005-0.007ct each and traditionally they would be sorted in parcels with average groupings of color and clarity.
D-F, IF, VVS; D/F VS
G-H, VS or G-H, SI

It would be difficult for me to seperate an H,VS2 from an I, SI1 in a 1.0mm diamond.

Consistency of the proportions is what I find important in melee. I want the table size and depth to be consistent throughout the parcel. That will enable the stones to reflect and refract light in the same way. Also, you may wish to request diamonds which do not fluoresce under LW or SW UV.

Bear in mind that India is manufacturing a lot of synthetic diamonds right now and you need to be buying from a firm with an excellent reputation to help guard against parcels being salted......


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 Post subject: Re: Diamond Grading course
PostPosted: Sun Jul 19, 2020 4:58 am 
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Thank you for the prompt response guys! I appreciate it.

Great, so this beginners diamond grading course will be worthwhile for when I start grading my melee diamonds.

Sorry, by star diamonds I was referring to the size. Apparently, what I’ve gathered online, -2 sieve diamonds are around 0.8 or 1.0 to 1.2mm whilst star size are 1.25-1.7mm and melee diamonds are 1.8mm and above. I could be remembering the sizes incorrectly by a tiny fraction. However, it’s interesting to know that star is also referred to as a cut by some wholesalers. I will be careful in using this term.

Thank you for explaining that cut will be a huge factor for the shine in melee diamonds, the supplier in India did mention this themselves previously and advised their cut would have been around Ex/Vg only however I will know for sure when the samples arrive next week and show it to my jeweller friend.


In terms of what Barbra has said, I was thinking the same that it must be very difficult to separate/grade the diamonds so I am concerned as to how I will be able to do it after practicing on 0.30ct’s. However I hope that I can figure it out with some practice.

Also, thank you for teaching me about the proportions, I will ask my jeweller friend to check this when the samples come. In terms of synthetics, my jeweller friend did warn me that a few synthetics do slip into every bag however he knows someone with a machine that will check my first few batches and the Indian supplier has promised that the diamonds are screened for synthetics already.


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 Post subject: Re: Diamond Grading course
PostPosted: Wed Jul 22, 2020 8:36 am 
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Barbra Voltaire, FGG wrote:
It has been my experience that a -2 sieve produces stones 1.0-1.2mm.
That is very small and no one would bother to grade each stone for color and clarity.

Those stones should average about 0.005-0.007ct each and traditionally they would be sorted in parcels with average groupings of color and clarity.
D-F, IF, VVS; D/F VS
G-H, VS or G-H, SI

It would be difficult for me to seperate an H,VS2 from an I, SI1 in a 1.0mm diamond.

Consistency of the proportions is what I find important in melee. I want the table size and depth to be consistent throughout the parcel. That will enable the stones to reflect and refract light in the same way. Also, you may wish to request diamonds which do not fluoresce under LW or SW UV.

Bear in mind that India is manufacturing a lot of synthetic diamonds right now and you need to be buying from a firm with an excellent reputation to help guard against parcels being salted......


Hi Barbra

I noticed that you mentioned about purchasing from firms with an excellent reputation in India. Would it be possible for you to advise me of a few firms that you are aware of? You can PM me if you would like.


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 Post subject: Re: Diamond Grading course
PostPosted: Wed Jul 22, 2020 2:54 pm 
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I don't buy or sell diamonds.
Sorry.
Perhaps someone else on the forum has a recommendation.


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