Announcement Our superstar- Garry Holloway!!

[Garry H (Cut Nut)]

Garry, where do you buy diamonds if you mainly see natural diamonds with Pavilion 41.7 /crown35.0?

On Rapaport B2B trading platform Sergey. Many companies do not give crown and pavilion angles. So the best I can do is show with depth %'s.
+68% are +62% depth & likely score well above HCA 2.0
There are more +63% than under 61.5% (which have a chance to score <2.0 HCA)

 

[marrduk24]

On Rapaport B2B trading platform Sergey. Many companies do not give crown and pavilion angles. So the best I can do is show with depth %'s.
+68% are +62% depth & likely score well above HCA 2.0
There are more +63% than under 61.5% (which have a chance to score <2.0 HCA)

Garry I love your data driven approach to things.

just plotted your data in a slightly different format. Nothing new but thought data geeks may enjoy it. As you noted, 68% of the diamonds have a depth > 62%. Another 37% diamonds have a depth between 60% to 62%. And 5% of the diamonds have a depth < 60%.

I personally always look for 61-62 depth and only 15% of the diamonds fall in that range.

 

[Garry H (Cut Nut)]

Garry I love your data driven approach to things.

just plotted your data in a slightly different format. Nothing new but thought data geeks may enjoy it. As you noted, 68% of the diamonds have a depth > 62%. Another 37% diamonds have a depth between 60% to 62%. And 5% of the diamonds have a depth < 60%.

I personally always look for 61-62 depth and only 15% of the diamonds fall in that range.

Great Thanks! For the record I looked at about 30 of the 62% depth stones on rap - those with crown and pavilion angles and about 50% had proportions that scored over HCA 2.0.

So to test your theory further - I just now checked 65 diamonds on that same search with 61% depths. I was surprised that 32 had bad HCA scores - almost always as a result of pavilion angles between 41.2 and 41.8.

Sergey I am afraid there are a very large number of diamonds along those bottom 3 rows. (but BTW you are referring to the red dot - that dot represents a diamond that I referred to later in the presentation that measures 6.3mm diameter (and as with so many GIA X cut diamonds - deeper than the supposed 63% depth cut off!)

 

[marrduk24]

Great Thanks! For the record I looked at about 30 of the 62% depth stones on rap - those with crown and pavilion angles and about 50% had proportions that scored over HCA 2.0.

So to test your theory further - I just now checked 65 diamonds on that same search with 61% depths. I was surprised that 32 had bad HCA scores - almost always as a result of pavilion angles between 41.2 and 41.8.

Sergey I am afraid there are a very large number of diamonds along those bottom 3 rows. (but BTW you are referring to the red dot - that dot represents a diamond that I referred to later in the presentation that measures 6.3mm diameter (and as with so many GIA X cut diamonds - deeper than the supposed 63% depth cut off!)

Interesting. I am sure not every diamond between 61-62 depth is cut well. But that’s a very interesting stat. I’d say my sweet spot would be crown Height of 14.7-15.5, pavilion depth of 43.43.5 and girdle of 2.5-3.5. That’s how I allocate my 61 to 62 depth.

BTW I ran a similar analysis to you but on 2 to 2.1 carat, D to I, FL to VS2, GIA 3ex diamonds and results were interesting

1. 1186 total diamonds
2. 563 had depth of 60 to 62. So almost half.

feels like better cut.

 

[Serg]

Garry,
Did you use repnet data just for mass range 1.00-1.00ct? How is big % such diamond from total RBC diamond on Rapnet? Do cutters sells best 1.00ct diamonds by Rapport? . How is different selling time on rapnet for good( total height 59%-62%) and very bad diamonds( 63%+)? I will clarify last question: for example averaging selling time for good diamonds is 2 months, when for bad diamonds it is 2 years. According you data there are 1771 good 1ct diamonds and 1439 bad 1cct diamonds. if selling time for these groups are in 12 times difference then cutters produce in 15 time more good diamonds than bad diamonds.
If you consider other important factors
"1) real mass range like 0.8-1,5ct
2) Cutters do not sell best diamonds on rapnet, cutters usually send to rapnet diamonds with highest discounts
3) some ugly diamonds are forever on rapnent "

You will receive ratio much higher than 1:15. Cutters are producing now much more good RBC than RBC with total height 63%+
It is classical example of GIGO. Garbage IN Garbage out.
you received wrong statement based on wrong approach and not you scare consumers .
it is not a good example of consumer education

 

[Garry H (Cut Nut)]

Garry,
Did you use repnet data just for mass range 1.00-1.00ct? How is big % such diamond from total RBC diamond on Rapnet? Do cutters sells best 1.00ct diamonds by Rapport? . How is different selling time on rapnet for good( total height 59%-62%) and very bad diamonds( 63%+)? I will clarify last question: for example averaging selling time for good diamonds is 2 months, when for bad diamonds it is 2 years. According you data there are 1771 good 1ct diamonds and 1439 bad 1cct diamonds. if selling time for these groups are in 12 times difference then cutters produce in 15 time more good diamonds than bad diamonds.
If you consider other important factors
"1) real mass range like 0.8-1,5ct
2) Cutters do not sell best diamonds on rapnet, cutters usually send to rapnet diamonds with highest discounts
3) some ugly diamonds are forever on rapnent "

You will receive ratio much higher than 1:15. Cutters are producing now much more good RBC than RBC with total height 63%+
It is classical example of GIGO. Garbage IN Garbage out.
you received wrong statement based on wrong approach and not you scare consumers .
it is not a good example of consumer education

If you watch the prices Sergey the old stone prices fall fast and they sell too.
Gargare sells too

 

[Serg]

Garry, could you please do similar research in Venus data base that you have access? How many RBC with total height above 63% does Venus ( or any other big Surat Manufacture except HK) make?

 

[Garry H (Cut Nut)]

Garry, could you please do similar research in Venus data base that you have access? How many RBC with total height above 63% does Venus ( or any other big Surat Manufacture except HK) make?

Sergey people on Pricescope are buying from 2 sources. Branded top cut quality diamonds from our much loved vendors.
Diamonds from data bases that are sourced from Rapaport (and some others like Rap).
Those are the very same diamonds and are of interest because more people buy them than the elite diamonds.
Diamonds in most mall stores are far worse than these.

 

[Serg]

If you watch the prices Sergey the old stone prices fall fast and they sell too.
Gargare sells too

Yes some cutters buy it finally for recut business. There is very big Surat company that cut polished diamonds for other Surat factories. Other Surat factories but these polished ( not semipolished) diamonds for recut because it is more profitable than to buy rough.
Cutter does use rapnet to find new buyers. Sorting in rapnet search is by price. So if somebody searches 1ct H VS RBC in rapnet he firstly sees diamonds with highest discounts. Cutters specially ! cut diamonds with huge negative spread to give highest possible discount to win 1st place in rapnet searching list. we do not cut to sell it. they cut it to receive a call from new buyer.

Most big factories does not produce RBC with total height 65% and even 63% because their internal appraisers limitations do not allow even to find such solutions in rough stage.

 

[Serg]

also the statement that diamonds with table 55%-60%, Total height 63%+ have angles like P41.8Cr35 is completely wrong.
please check Table 55-60, depth 63%+ , 1ct

here is 189 diamonds
113 off them( 62%) have pavilion angle 40.3 and less!

see for example

VG Round, 1.00ct, G, SI1, EX, VG, NON, -13.2%

VG Round, 1.00ct, G, SI1, EX, VG, NON, -13.2%

cutwise.com

1ct, P40 CR 38.7 Depth 64.2%





other interesting sample 1.5ct

VG Round, 1.50ct, I, SI1, EX, VG, NON, -11.9%

VG Round, 1.50ct, I, SI1, EX, VG, NON, -11.9%

cutwise.com

P39.9Cr38.1 Depth 63.4%

 

[Serg]

1.00ct GIA EX Cut, depth 63%+, Table 55-60

EX Round, 1.00ct, F, VVS2, EX, EX, NON, -6.8%

EX Round, 1.00ct, F, VVS2, EX, EX, NON, -6.8%

cutwise.com

P41.25Cr36.25=P41.5Cr35
It is not ugly diamond. May be it is not best for me, but personally I like it except spread.
if price is same as for 0.94ct Ex, it will very good option.
Such diamonds demand high discount for negative spread because they looks as 0.94ct.
But they do not demand high discount for Optical performance.

it is not same as P41.7Cr35

 

[marrduk24]

@Serg @Garry H (Cut Nut)

So I did analysis on inventory of one of the largest cutters in Surat. Selected D to I, 1 to 2.5 carats, FL to VS2, 3EX. There were 800 diamonds. See the results

1. Only 7% of the diamonds had depth > 63%. However I personally look for 61 to 62 and only 20% of the diamonds had depth of 61 to 62.
2. 42% of the diamonds had pavilion angle > 41.2.
3. Depth and Pav Angle is not the whole story but just to make the point - I looked at diamonds that had depth of 61-62 and pavilion angle of 40.6 to 41 and only 45 out of 800 diamonds (5%) met that criteria. Looking at it another way, even when diamonds met my depth criteria (160 diamonds), out of those 75% diamonds didn’t meet the pavilion criteria.

I could have continued it to further narrow down the list based on Crown Angle & Pav Angle combos but wasn’t sure what the point is

 

[Serg]

@Serg @Garry H (Cut Nut)

So I did analysis on inventory of one of the largest cutters in Surat. Selected D to I, 1 to 2.5 carats, FL to VS2, 3EX. There were 800 diamonds. See the results

1. Only 7% of the diamonds had depth > 63%. However I personally look for 61 to 62 and only 20% of the diamonds had depth of 61 to 62.
2. 42% of the diamonds had pavilion angle > 41.2.
3. Depth and Pav Angle is not the whole story but just to make the point - I looked at diamonds that had depth of 61-62 and pavilion angle of 40.6 to 41 and only 45 out of 800 diamonds (5%) met that criteria. Looking at it another way, even when diamonds met my depth criteria (160 diamonds), out of those 75% diamonds didn’t meet the pavilion criteria.

I could have continued it to further narrow down the list based on Crown Angle & Pav Angle combos but wasn’t sure what the point is

Thank you.
1)So just 7% diamonds have total depth above 63%. it does not confirm the Garry statement that most modern natural diamonds are steep/deep ( and specially close to P41.7Cr35 How you can see on the Garry map)
2) many from these 7% with Depth 63%+ could have very nice Optical Performance. Nothing wrong with Diamonds Pavilion 41.2 Crown 34.5.
could you split the group 63%+ into two groups 63-64% and 64%+? or even in 3 groups, 63-64, 64-65, 65%+

 

[marrduk24]

Thank you.
1)So just 7% diamonds have total depth above 63%. it does not confirm the Garry statement that most modern natural diamonds are steep/deep ( and specially close to P41.7Cr35 How you can see on the Garry map)
2) many from these 7% with Depth 63%+ could have very nice Optical Performance. Nothing wrong with Diamonds Pavilion 41.2 Crown 34.5.
could you split the group 63%+ into two groups 63-64% and 64%+? or even in 3 groups, 63-64, 64-65, 65%+

Serg

a different view. I have marked combinations I like. Roughly 7% of the diamonds fall in this region.

I would be keen to hear your view on what your absolute sweet spot is.

 

[Serg]

Serg

a different view. I have marked combinations I like. Roughly 7% of the diamonds fall in this region.

I would be keen to hear your view on what your absolute sweet spot is.

check line P40.8C36.5-P41.2Cr34.5-P41.6C32.5
and add range -0.4Pav+0.2 Pavilion degree( for example for Cr34,5 you will receive pavilion range 40.8-41.4)

P41.2Cr34.5 I like much more than P40.8Cr34.5
I do not like at all P40.4 Cr34.5 and specially P40.2Cr34.5, because such diamonds in clean conditions are darker and have less 'Life' than P41.6Cr34.5

 

[marrduk24]

check line P40.8C36.5-P41.2Cr34.5-P41.6C32.5
and add range -0.4Pav+0.2 Pavilion degree( for example for Cr34,5 you will receive pavilion range 40.8-41.4)

P41.2Cr34.5 I like much more than P40.8Cr34.5
I do not like at all P40.4 Cr34.5 and specially P40.2Cr34.5, because such diamonds in clean conditions are darker and have less 'Life' than P41.6Cr34.5

Is this what you mean?

 

[Serg]

Is this what you mean?

 

[marrduk24]

serg, one question. You definition of sweetspot is very different from HCA score. Now it’s fine if Garry had a different view from yours - two individuals can have a different view. But almost every vendor at least I know of that is known for manufacturing high optical quality diamond all seem to have a very aligned view, and that view generally matches HCA. Vendors I am talking about include - Eight Star, Victor Canera H&A, Crafted by Infinity, Whiteflash ACA, James Allen True Hearts etc.

 

[Garry H (Cut Nut)]

1.00ct GIA EX Cut, depth 63%+, Table 55-60

EX Round, 1.00ct, F, VVS2, EX, EX, NON, -6.8%

EX Round, 1.00ct, F, VVS2, EX, EX, NON, -6.8%

cutwise.com

P41.25Cr36.25=P41.5Cr35

For those that do not know, Sergey and me have had this argument for a decade.

Sergey I had a client yesterday with a similar diamond for retipping. So I took before and after cleaning photos.
As a 1ct diamond it would look smaller than 0.85ct - not 0.94ct when compared to a dirty shallower diamond.
When clean it has fantastic fire and not bad brilliance.

I suggest you do some real world experiments with the material that has the highest propensity to get and stay dirty of all known materials.

• Everyone's diamond gets dirty after minutes of wear.
• Most stay dirty 99% of their life.
• Slightly shallower cuts show the effects less than Tolkowsky 'ideal' cuts.
• Slightly deeper diamonds look much worse almost all the time.

My contribution to the world of diamonds is to improve the functional pleasure and enjoyment of diamonds. That is actually different to helping people just sell diamonds (when they are clean).

 

[Serg]

serg, one question. You definition of sweetspot is very different from HCA score. Now it’s fine if Garry had a different view from yours - two individuals can have a different view. But almost every vendor at least I know of that is known for manufacturing high optical quality diamond all seem to have a very aligned view, and that view generally matches HCA. Vendors I am talking about include - Eight Star, Victor Canera H&A, Crafted by Infinity, Whiteflash ACA, James Allen True Hearts etc.

Most vendors grade round diamonds in static position by monoscopic structure lights ( Firescope, IS, ASET, H&A,..)
Garry grades dirty diamonds. I do not see a reason to grade Fire in dirty diamonds. I did not see any Fire in dirty diamonds. I have not any idea that Fire HCA means

I compare clean diamonds in consumer's light conditions . Consumers have stereo vision and they tilt diamonds. It create significant difference in results . the difference come from approach and conditions. You can easy check that approach is better work for you if you will compare such diamonds without ASET, IS.

More details you can find in the article https://files.octonus.com/documents/GAA_Journal_V25_No3_Sept2013_V5.pdf

other works

Diamond Cut Study

IV Gemological Symposium, San Diego, Ca, USA, 27-30 Aug, 2006 Poster prezentation Study of Interdependence: Fancy-color Diamond Appearance, Cut, and Lighting Conditions Oral Prezentation Fancy-Col…

octonus.com

 

[Serg]

For those that do not know, Sergey and me have had this argument for a decade.

Sergey I had a client yesterday with a similar diamond for retipping. So I took before and after cleaning photos.
As a 1ct diamond it would look smaller than 0.85ct - not 0.94ct when compared to a dirty shallower diamond.
When clean it has fantastic fire and not bad brilliance.

I suggest you do some real world experiments with the material that has the highest propensity to get and stay dirty of all known materials.

• Everyone's diamond gets dirty after minutes of wear.
• Most stay dirty 99% of their life.
• Slightly shallower cuts show the effects less than Tolkowsky 'ideal' cuts.
• Slightly deeper diamonds look much worse almost all the time.

My contribution to the world of diamonds is to improve the functional pleasure and enjoyment of diamonds. That is actually different to helping people just sell diamonds (when they are clean).

Garry,

Do you a difference in Fire for such heavy dirty diamonds?
I did not see any declaimer in HCA promotions that HCA is for dirty diamonds Only.
How many consumers have understanding that HCA penalties best clean diamonds and gives handicap for clean dark shallow diamonds ?

Why do you use IS photos for clean diamonds when you explain HCA?

 

[Garry H (Cut Nut)]

I think you are being a bit silly now Sergey. We can just agree to disagree.

 

[nala]

I think you are being a bit silly now Sergey. We can just agree to disagree.

I don’t understand what you guys are disagreeing about. I’ve read this thread a few times and I can’t...

 

[Serg]

I think you are being a bit silly now Sergey. We can just agree to disagree.

Garry,
Are you fine? be happy.

 

[Serg]

Garry,

Do you a difference in Fire for such heavy dirty diamonds?
I did not see any declaimer in HCA promotions that HCA is for dirty diamonds Only.
How many consumers have understanding that HCA penalties best clean diamonds and gives handicap for clean dark shallow diamonds ?

Why do you use IS photos for clean diamonds when you explain HCA?

Sorry for misprint,
has to be

Do you see a difference in Fire for such heavy dirty diamonds?

 

[Serg]

I don’t understand what you guys are disagreeing about. I’ve read this thread a few times and I can’t...

I will simplify. Lets consider 3 round diamonds with modern proportions.

1st has Pavilion angle 40.8 Crown angle 34.5
2d has Pavilion angle 40.4 Crown angle 34.5
3d has Pavilion angle 41.2 Crown angle 34.5

There is a Big question: Which diamond is better?

The answer from most PS vendors : 40.8 Crown angle 34.5.
The answer from Garry: 40.8Crown angle 34.5, and 2d dirty diamond is much better than 3d dirty diamond.
My Answer : 41.2 Crown angle 34.5, we need grade clean polished diamonds in standard consumer light environments

Garry explanation: In consumer wearing conditions diamonds become a dirty a soon, that gives preferences to shallow diamonds like 40.4 Crown angle 34.5 compared with 41.2 Crown angle 34.5.
May be Garry mean something else, but I am too stupid to understand it. Sorry.

 

[Texas Leaguer]

While the cut aspect was a central premise in Garry's comments on the LGD panel, and also the reason this thread has veered deep into cut territory, I personally think cut factors are perhaps the least important considerations (long term) to the question about values of natural mined diamonds vs synthetics.

What I do find persuasive in Garry's premise is the valuation of diamond mines given the competition LGD represents for commercial quality diamonds in the jewelry industry. It makes perfect sense that LGD will out-compete natural in commercial sizes and qualities. They will be much cheaper and generally prettier resulting in a compelling value proposition to buyers on a budget. While the more affluent consumers with financial means will continue to strongly prefer natural, the overall market share that LGD take will be in the commercial area. And this part of production is critical to the overall profitability of most diamond mines. This trend will make it less likely that new mines are established or old mines rehabilitated, as both require enormous capital. Loss of the commercial market will shift the cost benefit analysis to the cost side, removing incentive to invest.

This factor will be the most important in driving the future price of natural diamonds, and as such, larger stones will become rarer and pricier. To me this analysis is very logical and the prediction very persuasive.

 

[Garry H (Cut Nut)]

While the cut aspect was a central premise in Garry's comments on the LGD panel, and also the reason this thread has veered deep into cut territory, I personally think cut factors are perhaps the least important considerations (long term) to the question about values of natural mined diamonds vs synthetics.

What I do find persuasive in Garry's premise is the valuation of diamond mines given the competition LGD represents for commercial quality diamonds in the jewelry industry. It makes perfect sense that LGD will out-compete natural in commercial sizes and qualities. They will be much cheaper and generally prettier resulting in a compelling value proposition to buyers on a budget. While the more affluent consumers with financial means will continue to strongly prefer natural, the overall market share that LGD take will be in the commercial area. And this part of production is critical to the overall profitability of most diamond mines. This trend will make it less likely that new mines are established or old mines rehabilitated, as both require enormous capital. Loss of the commercial market will shift the cost benefit analysis to the cost side, removing incentive to invest.

This factor will be the most important in driving the future price of natural diamonds, and as such, larger stones will become rarer and pricier. To me this analysis is very logical and the prediction very persuasive.

Thanks Bryan,
Here is a real world example.
My friends Ewen Tyler and Tom Redicliffe have found this amazing prospect, but because there are so many small pipes that need to be drilled, it is going to require a lot of money.
Add the region -about half way between Perth and Alice Springs - in the Gibson Desert with steep sand dunes.
We had one failed attempt at an IPO. Would love an angel investor to appear,
Ewen is referred to as the Father of Australian diamonds having found all 3 commercially operated diamond mines in Australia.
And you can now read all about him as he is the star of a new book.
Tom led the search at Merlin which has closed due to financial skulduggery. We want to get that back too!

Diamond exploration and discovery in Australia | GeoCrystal