Badly cut makes GIA/AGS color grade irrelevant?

[peridot83]

This came up in another post, and I thought I''d get some idea from people who look at tons more loose diamonds than I do .

GIA/AGS grade diamond color face down compared to a "D" baseline.

Now many on this forum state that if the diamond is cut well, color seen in the grading environment (through the sides and upside down) will NOT be very visible face up and set.

However if it is BADLY cut, is it possible for a diamond to somehow show MORE color face up than it does in the grading environment. I.e. is it possible for a badly cut GIA/AGS stone of a color grade "G" to actually look like an "I" face up.

OR no matter how badly cut the color of the stone, it will NOT be less than what is on the certificate. (obviously with room for slight subjective differences).

 

[diamondseeker2006]

I am no expert by any means, but I think the color will not appear lower than it''s color grade regardless of the cut. An excellent cut makes the stone appear whiter from the top. But hopefully an appraiser or jeweler will answer this with certainty for you!

 

[Regular Guy]

A Bushism...

Teach a child to read, and they will pass a reading test.



Maybe I''m one of those who inspired this post. But...though I agree with your post''s title, your annotation is irrelevant to it.

The function of a diamond is to sparkle beautifully in light. Forget color. If it doesn''t do that, I don''t care how white it is.

So, don''t buy a not well cut diamond...

But, not because, in not being well cut, it doesn''t allow the color to show well. Color is separate, and of some interest I''m sure (I bought a G).

 

[JohnQuixote]

Cut can influence body color either way, if body color is present.

A colorless diamond won’t appear to have any color (poor cut will just make it lifeless

).But when color is present (near-colorless and lower) there are proportions which cause that color to be trapped more. Diamonds with good proportions ‘face up’ more colorless because rays of light get in and out of the diamond more efficiently and with more intensity.If you put inefficient proportions on a diamond the light will leak or bounce around inside, causing body color to be entrapped and exaggerated.

For example, put a 41.8/34.X combo on a J color; it will look much more yellow and dark than a piece of the same rough cut to 40.8/34.X It's the opposite of improving face up color appearance (and the reason many diamond cutters raise their eyebrows at some of the combos allowed at the steep/deep border of GIA’s new EX grade).

This is also why fancy colored stones are cut to deeper or more shallow proportions than the ‘premium’ configs we’re used to when whiteness is the goal.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com

 

[peridot83]

Thank you so much, that''s the exact answer I needed

I''m aware for most of us here, that cut quality is most important. However, every once in awhile we get people who just want two things:

1. Size
2. Not yellow

I just wanted to make sure that cut quality CAN effect both components. Not only size, but can make the color face up worse than color on the certificate.

Therefore in diamonds "g or lower" one can''t discount cut when evaluating color. But D & Es (and maybe Fs?) should not be affected by cut quality.

 

[oldminer]

I pretty much don''t believe cutters are sloppy about their work. For the most part, they do a good job with the rough diamonds they have to work with. If they don''t they will either go broke or get fired. The configuration of the cut does play a large part in the face-up view of the body color. It is good cutting when a fancy color diamond shows more pleasing body color face up and identically cut colorless diamond would have a poorer rating for cut quality. Cut is not pure and simple for all diamonds. Cut must fit the hoped for outcome. You don''t make them all the same without regard to the specific circumstances of each piece of rough and its very individual characteristics.

We can make some very important cut parameter judgements for colorless range diamonds which most generaly are reflective of cut quality. For colored diamonds and for some specific other types, the cut is modified to make the outcome according to the market demand.