GIA triple excellent but score 3.6 in HCA!

[tunge]

just got myself a proposal diamond with the following specs

Report Type: GIA Diamond Grading Report
Round Brilliant
Measurements: 5.44 - 5.48 x 3.39 mm
Carat Weight: 0.62 carat
Color Grade: D
Clarity Grade: VS2
Cut Grade: Excellent
Proportions:
Depth: 62.1%
Table: 57%
Crown Angle: 35.0°
Crown Height: 15.0%
Pavilion Angle: 41.2°
Pavilion Depth: 43.5%
Star length: 50%
Lower Half: 75%
Girdle: Medium to Slightly Thick, Faceted
Culet: None
Polish: Excellent
Symmetry: Excellent
Fluorescence: None

I thought all was fine until i discovered this HCA calculator and keyed in my values and got a low low score of 3.6.

Am i in trouble?

 

[JulieN]

if you can compare to some ideal cuts, that is a good idea.

 

[Kelli]

Unfortunately, GIA''s excellent cut standards are not really up to par. I had one I couldn''t return and ended up getting it recut. If you can return this one I would. I really have to go to bed for tonight but take a look at this thread I just posted in on a related topic. https://www.pricescope.com/community/threads/help-with-our-diamond-purchase-please.102853/

 

[tunge]

been reading up more on the Holloway Cut Advisor...

i guess i shouldn''t be too worried abt the low score.

 

[MichelleCarmen]

Do you love the stone? That is what matters!

 

[Garry H (Cut Nut)]

Date: 12/22/2008 1:28:08 AM
Author: tunge
been reading up more on the Holloway Cut Advisor...

i guess i shouldn''t be too worried abt the low score.

the link Kelli posted suggests you should - she wrote this:
I had a GIA excellent cut that scored very similarly to yours on the HCA, and unfortunately, I did see that it wasn''t the best cut. It drove me nuts until I finally decided to have it recut. Since being recut, what a difference! I don''t want to be the bearer of bad news, but most diamonds will sparkle in the window by sunlight. If you want your diamond to be a stunner, my advice is to look for a better cut. CUT IS KING if you''re looking for the best sparkle you can get. I would not choose a diamond for color and size when the cut is lacking. To show you the difference cut can make, I''ll post before and after shots of mine. You''ll notice that the before picture looks pretty all blown up, but the "after" pic is SOOOO much brighter, and the brightness in real life makes such a difference. Also, the better cut you have in a diamond, the whiter it will appear. So an ideal cut H is most likely going to look whiter than a so-so cut F anyway. You can really see that in my pics.

Can you return it?
It will suffer mostly when it is dirty.

 

[tunge]

don't think i can return it... it's now getting set on the ring...

but i'm still happy with the diamond and the ring.

when i get the ring i'll post pics and seek comments.

 

[Garry H (Cut Nut)]

ignore us - we are extremist diamond junkies

 

[2.5rs]

Date: 12/22/2008 2:28:17 AM
Author: Garry H (Cut Nut)
the better cut you have in a diamond, the whiter it will appear. So an ideal cut H is most likely going to look whiter than a so-so cut F anyway. You can really see that in my pics.

Can you return it?
It will suffer mostly when it is dirty.

Garry Holloway FGAA DipDT
HCA and Ideal-scope developer
http://www.ideal-scope.com and
http://www.HollowayDiamonds.com.au

Is it true also that Strong Blue Fluorescence in a Colorless "D" stone will make it appear more white also, therefor helping it if it has a "Good" polish and "Good" symmetry?

 

[stone-cold11]

Date: 12/22/2008 2:54:17 AM
Author: 2.5rs

Is it true also that Strong Blue Fluorescence in a Colorless ''D'' stone will make it appear more white also, therefor helping it if it has a ''Good'' polish and ''Good'' symmetry?

No. How can a top grade colorless be more colorless? Becomes invisible?

 

[Lorelei]

Date: 12/22/2008 3:43:46 AM
Author: Stone-cold11

Date: 12/22/2008 2:54:17 AM
Author: 2.5rs

Is it true also that Strong Blue Fluorescence in a Colorless 'D' stone will make it appear more white also, therefor helping it if it has a 'Good' polish and 'Good' symmetry?

No, a D is as colourless as it gets, fluorescence will add colour ( blue) in some lights. Make sure the strong blue isn't making the diamond look hazy in some lighting conditions such as strong sunlight.

Good polish and symmetry and above are said to look the same to the naked untrained eye, fluoresence won't help it by the way.

 

[tunge]

Date: 12/22/2008 2:28:17 AM
Author: Garry H (Cut Nut)
ignore us - we are extremist diamond junkies

u guys are pros man!

but playing around with my values, keeping all values as they were and changing only the paviliion angle by 0.4 from 41.2 to 40.8 gave me excellent rating 1.7 (fr 3.6)... thta's a HUGE difference in rating for a small (maybe not so?) difference

 

[Garry H (Cut Nut)]

Date: 12/22/2008 3:47:24 AM
Author: Lorelei

Date: 12/22/2008 3:43:46 AM
Author: Stone-cold11

Date: 12/22/2008 2:54:17 AM
Author: 2.5rs

Is it true also that Strong Blue Fluorescence in a Colorless ''D'' stone will make it appear more white also, therefor helping it if it has a ''Good'' polish and ''Good'' symmetry?

No, a D is as colourless as it gets, fluorescence will add colour ( blue) in some lights. Make sure the strong blue isn''t making the diamond look hazy in some lighting conditions such as strong sunlight.

Good polish and symmetry and above are said to look the same to the naked untrained eye, fluoresence won''t help it by the way.

Minor point of correction Lorelei, if i might be so rude.
There is little or no reason to look at a nice diamond in direct sunlight.

The test for haziness should be in shaded sunlight - you can use a loupe and the shadow of your head - and see if the stone suffers a loss of transparency.

I have yet to see a diamond that has been cut and polished that looks good face up in direct sunlight.

 

[Garry H (Cut Nut)]

Date: 12/22/2008 4:52:21 AM
Author: tunge

Date: 12/22/2008 2:28:17 AM
Author: Garry H (Cut Nut)
ignore us - we are extremist diamond junkies

u guys are pros man!

but playing around with my values, keeping all values as they were and changing only the paviliion angle by 0.4 from 41.2 to 40.8 gave me excellent rating 1.7 (fr 3.6)... thta''s a HUGE difference in rating for a small (maybe not so?) difference

Yes - but recutting on that sized stone may not be economic.
Well done the stone would stay over 0.60ct, and when it is dirty is when you would mostly notice the difference. But it will still be a very nice diamond - far better than 80% of the diamonds you are likely to see.

 

[Lorelei]

Date: 12/22/2008 5:04:31 AM
Author: Garry H (Cut Nut)

Date: 12/22/2008 3:47:24 AM
Author: Lorelei

Date: 12/22/2008 3:43:46 AM
Author: Stone-cold11

Date: 12/22/2008 2:54:17 AM
Author: 2.5rs

Is it true also that Strong Blue Fluorescence in a Colorless 'D' stone will make it appear more white also, therefor helping it if it has a 'Good' polish and 'Good' symmetry?

No, a D is as colourless as it gets, fluorescence will add colour ( blue) in some lights. Make sure the strong blue isn't making the diamond look hazy in some lighting conditions such as strong sunlight.

Good polish and symmetry and above are said to look the same to the naked untrained eye, fluoresence won't help it by the way.

Minor point of correction Lorelei, if i might be so rude.
There is little or no reason to look at a nice diamond in direct sunlight.

The test for haziness should be in shaded sunlight - you can use a loupe and the shadow of your head - and see if the stone suffers a loss of transparency.

I have yet to see a diamond that has been cut and polished that looks good face up in direct sunlight.

LOL! Sure you can Garry, I welcome your advice and you are not rude!!

So thats the best way to test for negative effects for strong blue? Thanks as I can use that to advise posters in the future!

 

[strmrdr]

Date: 12/22/2008 4:52:21 AM
Author: tunge

Date: 12/22/2008 2:28:17 AM

Author: Garry H (Cut Nut)

ignore us - we are extremist diamond junkies

u guys are pros man!

but playing around with my values, keeping all values as they were and changing only the paviliion angle by 0.4 from 41.2 to 40.8 gave me excellent rating 1.7 (fr 3.6)... thta''s a HUGE difference in rating for a small (maybe not so?) difference

40.8 to 41.2 is a large step... here is 41.2

 

[strmrdr]

40.8

The question is if it is eye visible and the answer is in some lighting yes some no...

 

[Garry H (Cut Nut)]

Date: 12/22/2008 5:08:03 AM
Author: Lorelei

Date: 12/22/2008 5:04:31 AM
Author: Garry H (Cut Nut)


Minor point of correction Lorelei, if i might be so rude.
There is little or no reason to look at a nice diamond in direct sunlight.

The test for haziness should be in shaded sunlight - you can use a loupe and the shadow of your head - and see if the stone suffers a loss of transparency.

I have yet to see a diamond that has been cut and polished that looks good face up in direct sunlight.

LOL! Sure you can Garry, I welcome your advice and you are not rude!!

So thats the best way to test for negative effects for strong blue? Thanks as I can use that to advise posters in the future!

There is no manual on the topic and no gemology course (other than ones I teach) that i ever heard of that covers the topic Lorelei.
I have a paper coming out soon and after it is published I will ask the journal for permission to publish it here on the journal.

As part of the background I asked several lab directors and prominent gemo''s what % of Very Strong and S blue fluoro stones are hazy in shaded sunlight.
The answers (from 2 important labs) ranged from +90% to a tiny %.

Clearly there is no real background science or study in this field.

 

[Lorelei]

Date: 12/22/2008 5:14:59 AM
Author: Garry H (Cut Nut)

Date: 12/22/2008 5:08:03 AM
Author: Lorelei

Date: 12/22/2008 5:04:31 AM
Author: Garry H (Cut Nut)


Minor point of correction Lorelei, if i might be so rude.
There is little or no reason to look at a nice diamond in direct sunlight.

The test for haziness should be in shaded sunlight - you can use a loupe and the shadow of your head - and see if the stone suffers a loss of transparency.

I have yet to see a diamond that has been cut and polished that looks good face up in direct sunlight.

LOL! Sure you can Garry, I welcome your advice and you are not rude!!

So thats the best way to test for negative effects for strong blue? Thanks as I can use that to advise posters in the future!

There is no manual on the topic and no gemology course (other than ones I teach) that i ever heard of that covers the topic Lorelei.
I have a paper coming out soon and after it is published I will ask the journal for permission to publish it here on the journal.

As part of the background I asked several lab directors and prominent gemo''s what % of Very Strong and S blue fluoro stones are hazy in shaded sunlight.
The answers (from 2 important labs) ranged from +90% to a tiny %.

Clearly there is no real background science or study in this field.

Thanks Garry, I will look forward to reading your work on this subject!

 

[Ellen]

Date: 12/22/2008 2:28:17 AM
Author: Garry H (Cut Nut)
ignore us - we are extremist diamond junkies

I resemble that!

And about the flo in sun Gary, I know you have said don''t test it in the sun, however, every other professional opinion I''ve read on here says to do that, so it''s confusing.

But, even if we did rule out the sunshine test, and I had a stone with strong flo that ended up hazy in the sun, I would be very unhappy. I want my stone to look clear and sparkling no matter where I am, yanno? And I wonder if I would be alone on that....

 

[WinkHPD]

Date: 12/22/2008 5:04:31 AM
Author: Garry H (Cut Nut)

Date: 12/22/2008 3:47:24 AM
Author: Lorelei

Date: 12/22/2008 3:43:46 AM
Author: Stone-cold11

Date: 12/22/2008 2:54:17 AM
Author: 2.5rs

Is it true also that Strong Blue Fluorescence in a Colorless ''D'' stone will make it appear more white also, therefor helping it if it has a ''Good'' polish and ''Good'' symmetry?

No, a D is as colourless as it gets, fluorescence will add colour ( blue) in some lights. Make sure the strong blue isn''t making the diamond look hazy in some lighting conditions such as strong sunlight.

Good polish and symmetry and above are said to look the same to the naked untrained eye, fluoresence won''t help it by the way.

Minor point of correction Lorelei, if i might be so rude.
There is little or no reason to look at a nice diamond in direct sunlight.

The test for haziness should be in shaded sunlight - you can use a loupe and the shadow of your head - and see if the stone suffers a loss of transparency.

I have yet to see a diamond that has been cut and polished that looks good face up in direct sunlight.

Then I suggest you spend some time with Paul the next time you are in Antwerp. He can show you some!

Wink

 

[Ellen]

Date: 12/22/2008 10:20:49 AM
Author: Wink

Date: 12/22/2008 5:04:31 AM
Author: Garry H (Cut Nut)

Minor point of correction Lorelei, if i might be so rude.
There is little or no reason to look at a nice diamond in direct sunlight.

The test for haziness should be in shaded sunlight - you can use a loupe and the shadow of your head - and see if the stone suffers a loss of transparency.

I have yet to see a diamond that has been cut and polished that looks good face up in direct sunlight.

Then I suggest you spend some time with Paul the next time you are in Antwerp. He can show you some!

Wink

I think he just doesn't like that (dark) look Wink.

 

[:)]

Morning guys - weather is the pants today!
Tunge, sorry for the threadjack...

My (not so professional!) thoughts/pseudohypothesis on fluoro... (based somewhat on my knowledge of melanoma/UV/sunblock/screen data)

I am hesitant to tell people to evaluate fluoro in direct sunlight (caveat at the end of this). Often the days when sunlight is the brightest are days when there are no clouds, and thus the sky is blue - I believe that a lot of people think they get a 'blue' diamond effect from fluoro because of the actual reflection of the blue sky and thus would be more likely to 'see' effects from fluoro. Unfortunately most people associate only bright sunlight with UV prescence and sunburn (sunburn associated c/ UVB rays), melanoma, etc and will only wear sunscreen on those days, however UV is present outdoors whether it is cloudy or sunny, hence the reason we really need to wear sunblock/screen on a daily basis whether outdoors or not. Sun sends us UV A, B, and C, of which UVA is actually the one that reaches us in the highest proportion of the UV spectrum. Certainly when the sun is directly overhead is when the UV is the strongest, but again there is still UV bouncing /reflected around whether it is stong sun or not (and its presence can be intensified with reflections off snow, water) - I believe that fluoro testing on diamonds is done in the UVA range (365 nm) in the labs (if I read GIA correctly - please correct me if I am wrong.)

It is not actually bright sun itself that you need for the fluoro, but the UV spectrum portion. UV light is still dispersed in the shade provided you are not behind a UV blocking or filtering device. UVB is filtered by glass (such as riding in an auto), however UVA is not filtered by glass (caveat- we have learned over the years that UVA is actually much more damaging to cells (beyond even wrinkles) than we used to be aware of).

That said, I think if we are telling people to look for UV effects in direct sunlight, then we need to be telling them additionally to use a UV lexan piece or comparable filter (Rockdoc is the one whom I used to note recommended lexan.) From what I have been able to tell reading materials data sheets, lists of lexan for sale, it is possible that not all lexan filters UV, although I do not know this for sure - I would just make sure to get one that is indeed listed as UV filtering. It could be used by looking in direct sunlight for haziness, then covering (in the same setting) with the lexan that would at least decrease the presence of UV (still would not filter out what is bouncing around, but would at least filter what is coming directly down prior to getting absorbed by some surroundings, etc) to see if any 'haziness' seen goes away.

Of course if we wanted to do it in indirect light maybe we could have them stand in indirect light in the snow, or next to a pool or lake! (to maximize UV reflection)

I think it is really difficult to instruct those of us 'nonprofessionals' what to look for with UV light and haziness or blueishness (or whatever color), etc - this is probably the best we can do for now, although my preference would be to take it to a truly professional (independent!) appraiser for an evaluation because he/she is more familar with what exactly to look for.

I wish I had some (fluoro and nonfluoro) diamonds that I could do an experiment with - evaluating them in direct sunlight, then in direct with some uv lexan, then in indirect sunlight (and also in direct next to a pool or a lake or something) to record effects, then have complete novices evaluate their findings in the same controlled setting to see how well they are able to determine any differences... I think it is just really hard for us to know what we are really looking for, and we may take something (such as a dirty pavillion) to show 'haziness' due to fluoro (when in fact it was just due to a greasy pavillion) when evaluating...

 

[diamondseeker2006]

Excellent post, ! I think you are very correct that sometimes we non-pros do not even know what to look for when it comes to floro!

 

[:)]

Date: 12/22/2008 1:10:22 PM
Author: diamondseeker2006
Excellent post, ! I think you are very correct that sometimes we non-pros do not even know what to look for when it comes to floro!

Aw - Thanks DS! That means a lot coming from you!

 

[Lorelei]

Date: 12/22/2008 1:10:22 PM
Author: diamondseeker2006
Excellent post, ! I think you are very correct that sometimes we non-pros do not even know what to look for when it comes to floro!

Absolutely! As consumers we have real limitations, and it especially now RT has grown so much and fluorescence questions frequently come along, it is good that discussions like this arise so we can get opinions from experts who have actual experience in this area, in order that we can pass the best advice on to those who seek it. The standard advice has always seemed to be to test for any haziness/ negative effects in strong sunlight for SB fluorescence as Ellen mentioned ( for those who don't have a trusted vendor or appraiser to inspect the diamond), but maybe we need a rethink of what the usual advice given should be?

GREAT post doc!!!

 

[WinkHPD]

Date: 12/22/2008 11:38:39 AM
Author:


I think it is just really hard for us to know what we are really looking for, and we may take something (such as a dirty pavillion) to show ''haziness'' due to fluoro (when in fact it was just due to a greasy pavillion) when evaluating...

I am not sure whether to think you might be in the medical field or perhaps the cosmetic field, but that was one INFORMATIVE post about the UVA and UVB and your last sentence made it clear that with all of that knowledge you were still not sure what to be looking for, so allow me please to jump in. (Hmmm, that sounds a little wierd. My intent is to compliment you on the post and the very good information in there, and to help you and others to understand more about what you are looking for. Please hear my intention)

When we look for an overblue, it is instantaneous and horrible if it exists.

The stone will look like you dropped in oil and that the oily mess is all over the stone. It will look sometimes more translucent than transparent and it will be UGLY! You go back inside and it looks beautiful again. There will be no missed diagnosis caused by a greasy pavilion, it is PAINFULLY obvious when it is seen, and fortunately, it is so exceedingly rare that most people will never see it.

This phobia against fluorescence is a residual effect from the investment craze days of the late seventies when shoe clerks were converted to diamond experts selling diamonds from boiler room phone shops in a week. No time to train them to actually understand a diamond and even less time to actually look at the stone and see if it was a beauty or a dog, so all fluorescence was cursed and spat upon until those that followed never bothered to look and question what was now concidered common knowledge. Sigh.

Those of us used to paying more and selling the beauties for more were marginalized and pushed to one side and this now nearly three decade injustice to the beautiful stones is finally being exposed for the horse hockey that it is thanks to the wonder of the Internet and its access to every one. As it stands now, the fluorescent stones are still available at a slight discount in the higher colors and may actually always be so, but it is not because they are not fantastic, it is just because that is now what the market has come to expect.

But never fear, direct sunlight or in the shade of a tree or wherever, if the diamond is an overblue, you will need no loupe or other equipment to see it, and you will NOT like what you see.

Wink

 

[Lorelei]

Thank you Sir Wink for such an informative post!!! So it is actually pretty obvious then if a diamond does show this effect!

 

[WinkHPD]

Date: 12/22/2008 10:28:50 AM
Author: Ellen

Date: 12/22/2008 10:20:49 AM
Author: Wink

Date: 12/22/2008 5:04:31 AM
Author: Garry H (Cut Nut)

Minor point of correction Lorelei, if i might be so rude.
There is little or no reason to look at a nice diamond in direct sunlight.

The test for haziness should be in shaded sunlight - you can use a loupe and the shadow of your head - and see if the stone suffers a loss of transparency.

I have yet to see a diamond that has been cut and polished that looks good face up in direct sunlight.

Then I suggest you spend some time with Paul the next time you are in Antwerp. He can show you some!

Wink

I think he just doesn''t like that (dark) look Wink.

Dark? Maybe you should spend some time with Paul too! I will admit to loving the look of a well cut diamond under the shade of a green leafed tree, but the real reason for not looking at an incredible cut diamond in the sun is not to hurt your eyes...

Wink

 

[WinkHPD]

Date: 12/22/2008 2:07:51 PM
Author: Lorelei
Thank you Sir Wink for such an informative post!!! So it is actually pretty obvious then if a diamond does show this effect!

Painfully.