Help needed - feathers and internal graining

[Mika1]

Hello,

First of all, thanks very much for a great forum particularly to the regular contributors!

I need help on two things that I have seen on a GIA report.

Firstly should I be worried about a feather next to the girdle (see pic below, on the left hand side of the diamond)?

Secondly for a GIA VS2, is internal graining ever a significant issue?

Thanks in advance,

Mik

 

[diamondseeker2006]

I wouldn't worry too much about the inclusions because that stone has other potential problems in terms of cut. It likely has leakage and you absolutely need an idealscope image before considering a purchase. I used the HCA tool to check out the diamond:

https://www.pricescope.com/tools/hca

Light Return: Fair
Fire: Good
Scintillation: Good
Spread or diameter for weight: Very Good
Total Visual Performance: 5.5 - Good - Only if price is your main criterion

You want to see Excellent for the first three items and Very Good for spread. Total visual performance should be 2.0 or less, but sometimes up to 2.5 is okay, too, as long as you have the idealscope image.

Just to give you a guideline to help you fall into the <2.0 range, look for these numbers or close to them:

Table: 54-58

Depth: 60-62.3

Crown angle: 34-35.0

Pavilion angle: 40.6-41.0

The stone you posted has too high of a crown angle to work with it's pavilion angle. It is also deeper than I would want as greater depth can result in a smaller face-up size (diameter).

 

[Diamond_Hawk]

Firstly should I be worried about a feather next to the girdle (see pic below, on the left hand side of the diamond)?

Secondly for a GIA VS2, is internal graining ever a significant issue?

First of all - read all of diamondseeker2006's post - absolutely correct. If you are considering this diamond for purchase, you will want to take all of that info into account.

If you need more info on this particular diamond - I do want to help you on your specific questions regarding the inclusions, but I need a bit more information.

When you ask "should you be worried" - are you speaking in terms of light performance, durability, general appearance, resale, or other? And the same for "significant issue" - in what way?

The assumption is usually that you are asking about light performance but without the data from an Idealscope or an ASET we cannot give you any more information than what DS2006 has already provided. If you are asking about other aspects, please be specific and I am sure you will get those questions answered.

 

[Mika1]

DS2006 & DH - thanks both.

Obviously my knowledge was too basic to understand all the potential issues. I was worried about light performance changes caused by internal graining and durability risks of having feathers near the girdle.

I did not get the importance of the HCA score for an excellent cut / polish and thanks very much for pointing out that. I noticed that the HCA score is calculated on a very good polish, but I gather from you that having an excellent vs. very good polish does not make a big difference.

Sounds like this one is worth giving a miss.

 

[Lorelei]

DS2006 & DH - thanks both.

Obviously my knowledge was too basic to understand all the potential issues. I was worried about light performance changes caused by internal graining and durability risks of having feathers near the girdle.

I did not get the importance of the HCA score for an excellent cut / polish and thanks very much for pointing out that. I noticed that the HCA score is calculated on a very good polish, but I gather from you that having an excellent vs. very good polish does not make a big difference.

Sounds like this one is worth giving a miss.

Hi Mika,

I agree with the comments DS and Brian made earlier. I am personally not worried about any potential durability risks or transparency issues with this diamond. That it says ' internal graining not shown' implies it is probably not an issue and is just mentioned for completeness.

What I am concerned with is the potential for light leakage due to that steep/deep angle combo but we do have to consider this is a big stone and therefore more rare and the price. Depending on the asking price and the quality of the cut you seek, it might be worth getting an Idealscope image to see if any leakage is present and if so, how much. Would it be possible to ask the vendor for some images?

 

[Mika1]

Lorelei - thanks for that.

I'm going through BN and I know it is hit and miss... and hence no idealscope.

It would set me back around $31k, which was 13% discount on a price-per-carat from PS tables.

 

[Mika1]

This was the alternative I had in mind - at around 34% premium and significantly smaller I wasn't sure about it.

It also has a lot more feathers.

 

[Lorelei]

This was the alternative I had in mind - at around 34% premium and significantly smaller I wasn't sure about it.

It also has a lot more feathers.

Hi Mika,

The second diamond is perhaps a ' safer' bet proportionwise, but as you mention, it is smaller. The feathers aren't usually a cause for concern although it never hurts to get an independent expert to check it out, especially as it's a big diamond, you would need to check carefully it is eye clean to your specs too. You could order the first stone, see if you like it, then send it to an appraiser of your choosing for their expert opinion on the cut quality and other aspects of the stone - make sure you find an appraiser that has expertise in evaluating cut. It would be well worth it for a purchase of this magnitude plus BN do have an excellent return policy which would give you time to do this.

 

[Mika1]

Thanks Lorelei - much appreciated

 

[Lorelei]

Thanks Lorelei - much appreciated

You are most welcome, good luck and let us know what happens!