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Polishing An Unpolished Girdle And Gia Cerification


tweetybird
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Hi,

 

My mother gave me her diamond to use for my engagement ring. It is about a 1 carat diamond with a beautiful round brilliant cut. The only thing is that since it is from the early 1970s, it has not been officially certified, and it has an unpolished girdle (that is visible to the naked eye). My questions are:

1) We were told that it would be a good idea to get the unpolished girdle polished. Is this a good idea, and is it safe for the diamond? Any ideas on what this typically costs?

2) We are planning to get it certified with GIA. Is it worth the expense and time to get an official certification done? Any ideas on cost?

 

Thank you in advance for your help...

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HI Tweety,

I don't necessarily think either thing might be called for.

As far s the girdle- there's nothing at all "wrong" with a non polished girdle- providing it's not a sloppy one.

 

The grading by GIA is a great idea if it's a high quality diamond.

I'd find a qualified appraiser in your area to have a look on both counts-

 

 

If it's a high color and clarity- say above H/Si2-

then a GIA report may be in order.

 

If the girdle is having a negative impact on the cut, the appraiser should be able to guide you there too.

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Whether it’s worth the trouble to polish the girdle is a slightly complicated question. Usually not unless you’re trying to sell it and maybe not even then. Seek out an appraiser who understands cutting.

 

In most cases I sort of doubt that a GIA exam will help you much either, again unless you’re trying to sell it and as David points out, then only if it’s a fairly high end stone. As with the above, start with a session with an appraiser.

 

Neil

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Anytime you put a diamond to the cutting wheel there is risk.

 

Since you don't know the clarity of your diamond, its characteristics/topology, and whether there are any sensitive areas along the girdle area, it's wise to have a knowledgeable appraiser evaluate your diamond.

 

In addition, depending on the origin of the diamond rough, polishing the girdle in colors I and below will actually bring out more color and hue thus making the stone appear darker.

 

Evaluate this carefully before you go forth and girdle polish your stone.

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Intersting info from Barry.

 

Followup questions to this post's info:

As a real example, take a 5.25 stone with a color assessed to be R-S. VS1 clarity.

It has an even, warm, light yellow color to it(neither bright nor dark). From the side it has

more color evident, while it faces up light yellow through the fire.

The girdle is uniformly medium for the size of the stone. The girdle is frosty.

 

Hypothetically, if the girdle was polished, it would exhibit more color face up?

But it would also be a bit darker(saturated) in the color?

 

Would GIA assess the former R-S stone as an even deeper color grade?

Like going from an R-S to a T-U color?

 

Also, would it be possible to go from a light yellow to a FANCY light yellow?

Or would the darkening-effect that was mentioned prevent it from attaining a FANCY designation?

 

 

Jay Johnson

 

 

...

In addition, depending on the origin of the diamond rough, polishing the girdle in colors I and below will actually bring out more color and hue thus making the stone appear darker.

 

Evaluate this carefully before you go forth and girdle polish your stone.

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Intersting info from Barry.

 

Followup questions to this post's info:

As a real example, take a 5.25 stone with a color assessed to be R-S. VS1 clarity.

It has an even, warm, light yellow color to it(neither bright nor dark). From the side it has

more color evident, while it faces up light yellow through the fire.

The girdle is uniformly medium for the size of the stone. The girdle is frosty.

 

Hypothetically, if the girdle was polished, it would exhibit more color face up?

But it would also be a bit darker(saturated) in the color?

 

Would GIA assess the former R-S stone as an even deeper color grade?

Like going from an R-S to a T-U color?

 

Also, would it be possible to go from a light yellow to a FANCY light yellow?

Or would the darkening-effect that was mentioned prevent it from attaining a FANCY designation?

 

 

Jay Johnson

 

Hi Jay,

First of all, whoever assessed the color is not in line with GIA standards.

It's either an S-T, or a U-V.

What this means is that the assessment is called into question. The stone might be lighter, or darker.

 

You did not mention the shape of your diamond..... If it's a round diamond there's not much to be done....

I'd also ask if the stone is fluorescent.

 

GIA grades Fancy Colors "Face Up"- as opposed to looking thru the back as they would on a colorless, or near colorless diamond.

 

In terms of a polished girdle, it's pretty much a "no brainer" that any Radiant, Cushion, Pear Shape will have a polished, or faceted girdle if the stone is cut to bring out the color.

There are also other facets which are also helpful in focusing the body color of the diamond.

Certain cutters- ones that specialize in Fancy Colors- have it down pretty well.

If the cutter has done his job well, it's possible a diamond that might have been Y-Z could move up to Fancy Light Yellow with some improvements to the cut.

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