diamond grading on the fringe....

[calisurf]

Just had a question in regards to diamond grading where the grading lies on the fringe. For example.

Colors F and G (Colorless to Near Colorless)
Clarity SI2 to I1 (slightly included to included)

I don''t know exactly how to put this, but is there any reason a certifier will bump up the grade just to make the next step. I have always been a little paranoid about this. And the stone I purchased just validated my paranoia.



For example, I just purchased a stone, that was really good except for the clarity, which was SI2.
The stone only had a mini-cert. I really wanted to get a more detailed report so we had it sent to gia. The dealer said I could''t get a gia report unless i bought it first. So I did and it came back as an I1.

A second question is who makes the mini-cert, is it the cutter? If so my scenario would kind of make sense.

On clarity is there a science to how to grade clarity, of all the c''s.This seems to be the most subjective.

So many questions my head is starting to hurt. Any thoughts are appreciated. Thanks in advance.

 

[diamondlil]

Just curious, was the mini-cert EGL or GIA? I did not realize GIA did mini certs.

Diamondlil

 

[Mara]

EGL does mini-certs...I don't think AGS or GIA did. I would not be surprised if it was a mini cert from EGL as they are notoriously lax on their grading...which is why their diamonds are priced cheaper than AGS or GIA stones for the most part.

The mini-cert should come from a grading lab...what does the mini-cert say.

Don't worry about F to G...G is still very white and some argue that it should not be lumped together with H/I/J....

But for clarity it is definitely subjective...to the graders eyes...since grading is done by humans, one may see one thing and another will see something else. SI2 / SI3 grades are sneaky...they may be borderline I1 at times. GIA is notoriously more strict on clarity grading, and EGL is notoriously lax (some labs)....

Look at the pricescope tutorial for clarity grading info. Basically I1 means that inclusions are visible with the naked eye. SI means that some may be visible--depending on the grade and the inclusion and where it is placed. VS means you won't see anything with naked eye.

Good luck!

 

[calisurf]

Thanks for the replies.
Great Advice...
It was a PGS minicert.

No harm or foul, I got a refund today.
Now I have to start looking again....sigh...

 

[diamondlil]

Well, this would explain an SI2 then getting an I1 if it were a mini-cert from EGL and the stone was then sent to GIA for a full workup. With EGL usually being more lax, that would make sense. Also, if you had a mini-cert, wouldn't the lab (EGL) have all the information on file to give a complete certification without having to send the stone back? I'm thinking the original cert was a mini from EGL, then the stone was sent to GIA for the full cert, and they gave it 1 grade lower on the clarity. And I'm still old school and don't believe in SI3 grades.

Diamondlil