Why depth is not the opposite of spread in a fancy shape?

[oldminer]

Sergey, Vine is excellent, too.


So Garry, do you think we ought to provide a Dollars per square millimeter comparison calculation? Maybe you can build it into the HCA. No doubt DiamCalc could convert it Euros, Yuan, Rupees, Yen, etc.

 

[Garry H (Cut Nut)]

Date: 4/14/2010 8:05:46 PM
Author: oldminer
Sergey, Vine is excellent, too.


So Garry, do you think we ought to provide a Dollars per square millimeter comparison calculation? Maybe you can build it into the HCA. No doubt DiamCalc could convert it Euros, Yuan, Rupees, Yen, etc.

You will keep, Enry Iggins!

 

[Garry H (Cut Nut)]

Date: 4/14/2010 12:13:58 PM
Author: Serg


% should be from reference diamond.

take two diamonds ( in current % system from reference diamond)

-20% spread and +20% spread
0.8 ct ( -0.20ct) and 1.2 ct( 0.20ct)
in both cases 20% means same 0.2ct

But in your system same +/- 0.2ct will -25% and 17%
I think it is more confusing ( even if it is more easy for calculations)

Because % from reference system is not easy for calculations, Diamcalc gives Spread in Carats and in %( from reference diamond) In Same Time

There is still no consensus.

Surface area in square mm can be misleading.

% spread currently used on InHouse stones searches can be confusing as pointed out by CCL.

What is wrong with just the carat weight difference for the standard round. Or even the weight of a standard round with the same calculated spread?

It is worth remembering that this is only accurate for rounds, princess and baguette cuts (which are rarely ever listed individually) and there is an approximation for emerald cuts and asschers (becuase we never know how big the corners are).
Should we do the same guestimate computation for Ovals, Marquise and Pear shapes?

Finally I agree that there should be a mouse over description as to what the spread result we give actually means.

 

[ChunkyCushionLover]

Date: 4/17/2010 12:13:03 AM
Author: Garry H (Cut Nut)

Date: 4/14/2010 12:13:58 PM
Author: Serg


% should be from reference diamond.

take two diamonds ( in current % system from reference diamond)

-20% spread and +20% spread
0.8 ct ( -0.20ct) and 1.2 ct( 0.20ct)
in both cases 20% means same 0.2ct

But in your system same +/- 0.2ct will -25% and 17%
I think it is more confusing ( even if it is more easy for calculations)

Because % from reference system is not easy for calculations, Diamcalc gives Spread in Carats and in %( from reference diamond) In Same Time

There is still no consensus.

Surface area in square mm can be misleading.

% spread currently used on InHouse stones searches can be confusing as pointed out by CCL.

What is wrong with just the carat weight difference for the standard round. Or even the weight of a standard round with the same calculated spread?

It is worth remembering that this is only accurate for rounds, princess and baguette cuts (which are rarely ever listed individually) and there is an approximation for emerald cuts and asschers (becuase we never know how big the corners are).
Should we do the same guestimate computation for Ovals, Marquise and Pear shapes?

Finally I agree that there should be a mouse over description as to what the spread result we give actually means.

Surface Area in square mm is not misleading at all it just doesn't give you a frame of reference for comparison.
Spread in carats is good for comparing the same weight diamonds against an ideal tolk round, but it doesn't give you the proper relative size difference between two different carat weight diamonds.

SA/Carat can be misleading and is a metric I would not use.

Any objections to providing both spread in carats and surface area in two different columns?
The legend is also important for spread, please provide the text of what would be used in the rollover.

Also you can't really provide spread or SA for anything but round and princess and baguette unless the output of Diamcalc is fed into the database for the other shapes. Just too much error in the estimates.

Overall this is a useful thread for considering spread differently. I bet many consumers are scared off by the "tradition" of rejecting fancy diamonds with greater than 70% depth. With surface area and spread they would understand that some fancy shapes have the same spread as a tolk round or more despite a fancy depth % of 70 - 75%.

 

[Serg]

Date: 4/17/2010 12:52:03 PM
Author: ChunkyCushionLover

Date: 4/17/2010 12:13:03 AM

Author: Garry H (Cut Nut)

Date: 4/14/2010 12:13:58 PM

Author: Serg



% should be from reference diamond.


take two diamonds ( in current % system from reference diamond)


-20% spread and +20% spread

0.8 ct ( -0.20ct) and 1.2 ct( 0.20ct)

in both cases 20% means same 0.2ct


But in your system same +/- 0.2ct will -25% and 17%

I think it is more confusing ( even if it is more easy for calculations)


Because % from reference system is not easy for calculations, Diamcalc gives Spread in Carats and in %( from reference diamond) In Same Time

There is still no consensus.


Surface area in square mm can be misleading.



% spread currently used on InHouse stones searches can be confusing as pointed out by CCL.


What is wrong with just the carat weight difference for the standard round. Or even the weight of a standard round with the same calculated spread?


It is worth remembering that this is only accurate for rounds, princess and baguette cuts (which are rarely ever listed individually) and there is an approximation for emerald cuts and asschers (becuase we never know how big the corners are).

Should we do the same guestimate computation for Ovals, Marquise and Pear shapes?


Finally I agree that there should be a mouse over description as to what the spread result we give actually means.

Surface Area in square mm is not misleading at all it just doesn't give you a frame of reference for comparison.

Spread in carats is good for comparing the same weight diamonds against an ideal tolk round, but it doesn't give you the proper relative size difference between two different carat weight diamonds.


SA/Carat can be misleading and is a metric I would not use.


Any objections to providing both spread in carats and surface area in two different columns?

The legend is also important for spread, please provide the text of what would be used in the rollover.


Also you can't really provide spread or SA for anything but round and princess and baguette unless the output of Diamcalc is fed into the database for the other shapes. Just too much error in the estimates.


Overall this is a useful thread for considering spread differently. I bet many consumers are scared off by the 'tradition' of rejecting fancy diamonds with greater than 70% depth. With surface area and spread they would understand that some fancy shapes have the same spread as a tolk round or more despite a fancy depth % of 70 - 75%.

re:Spread in carats is good for comparing the same weight diamonds against an ideal tolk round, but it doesn't give you the proper relative size difference between two different carat weight diamonds.

Spread in carats gives best( for my opinion) option to compare relative size difference between two different carat weight diamonds.
For my opinion information: what one diamond looks as 1.02ct round diamond and second as 1.5 ct round diamond ( or 1.05ct round diamond) is more useful for buyer than information in sq. mm( at least until time when we receive pricelist per sq. mm)

 

[ChunkyCushionLover]

Date: 4/17/2010 3:12:29 PM
Author: Serg

Date: 4/17/2010 12:52:03 PM
Author: ChunkyCushionLover

Date: 4/17/2010 12:13:03 AM

Author: Garry H (Cut Nut)

Date: 4/14/2010 12:13:58 PM

Author: Serg



% should be from reference diamond.


take two diamonds ( in current % system from reference diamond)


-20% spread and +20% spread

0.8 ct ( -0.20ct) and 1.2 ct( 0.20ct)

in both cases 20% means same 0.2ct


But in your system same +/- 0.2ct will -25% and 17%

I think it is more confusing ( even if it is more easy for calculations)


Because % from reference system is not easy for calculations, Diamcalc gives Spread in Carats and in %( from reference diamond) In Same Time

There is still no consensus.


Surface area in square mm can be misleading.



% spread currently used on InHouse stones searches can be confusing as pointed out by CCL.


What is wrong with just the carat weight difference for the standard round. Or even the weight of a standard round with the same calculated spread?


It is worth remembering that this is only accurate for rounds, princess and baguette cuts (which are rarely ever listed individually) and there is an approximation for emerald cuts and asschers (becuase we never know how big the corners are).

Should we do the same guestimate computation for Ovals, Marquise and Pear shapes?


Finally I agree that there should be a mouse over description as to what the spread result we give actually means.

Surface Area in square mm is not misleading at all it just doesn''t give you a frame of reference for comparison.

Spread in carats is good for comparing the same weight diamonds against an ideal tolk round, but it doesn''t give you the proper relative size difference between two different carat weight diamonds.


SA/Carat can be misleading and is a metric I would not use.


Any objections to providing both spread in carats and surface area in two different columns?

The legend is also important for spread, please provide the text of what would be used in the rollover.


Also you can''t really provide spread or SA for anything but round and princess and baguette unless the output of Diamcalc is fed into the database for the other shapes. Just too much error in the estimates.


Overall this is a useful thread for considering spread differently. I bet many consumers are scared off by the ''tradition'' of rejecting fancy diamonds with greater than 70% depth. With surface area and spread they would understand that some fancy shapes have the same spread as a tolk round or more despite a fancy depth % of 70 - 75%.

re:Spread in carats is good for comparing the same weight diamonds against an ideal tolk round, but it doesn''t give you the proper relative size difference between two different carat weight diamonds.

Spread in carats gives best( for my opinion) option to compare relative size difference between two different carat weight diamonds.
For my opinion information: what one diamond looks as 1.02ct round diamond and second as 1.5 ct round diamond ( or 1.05ct round diamond) is more useful for buyer than information in sq. mm( at least until time when we receive pricelist per sq. mm)

Serg,


It doesn''t do a consumer much good to know its 1.05 + 0.1=1.15 Carat and the other one is 1.5ct - 0.1 = 1.4 carats.
How much bigger is the 1.5 to the 1.05 in surface area difference?

 

[Garry H (Cut Nut)]

Date: 4/17/2010 7:10:06 PM
Author: ChunkyCushionLover
Serg,


It doesn''t do a consumer much good to know its 1.05 + 0.1=1.15 Carat and the other one is 1.5ct - 0.1 = 1.4 carats.
How much bigger is the 1.5 to the 1.05 in surface area difference?

CCL it is unlikely a consumer will be comparing these stones in Sergey''s e.g.
unless say they are comparing 1ct D VVS and 1.5ct H SI etc

I still do not understand why anyone would considerer it difficult to do the sum based on the carat weight variation?

And I still do not see the relevance of surface area when it is typically say 32 vs 31 or 33. It means very very little.
Where as carat weight has a direct linkage to value.

 

[Serg]

CCl,
re;Serg,


It doesn't do a consumer much good to know its 1.05 + 0.1=1.15 Carat and the other one is 1.5ct - 0.1 = 1.4 carats.
How much bigger is the 1.5 to the 1.05 in surface area difference?

1) 1.5 ct round has in 1.8 times bigger price than 1.05 ct round. This is very important and helpful information for consumer
2) 43sq.mm is clear bigger than 33 sq.mm . But is bigger enough or big enough ?,consumer can not decide by numbers in sq. mm. He needs see diamonds and compare. In such case it is very easy compare without any spread

a) 1.05 ct round has bigger price then 1.02ct round on 3%, what is again important information for consumer( is big or small difference depends from consumer only and he can decide )
b) if difference in mass 3%, difference in sq mm is 2%. how is helpful information : first diamond has 34 sq mm , second diamond has 33.4 sq mm? It gives information just what first diamond is bigger. But anybody know what 1.05 ct round is bigger than 1.02 ct round( same proportions). Where is any additional information what sq.mm gives?

even beginner software developer can create for you simple software which recalculate mass of round diamond to sq mm.
you need just inform him about diameter for 1ct round cut( or sq. mm for 1ct round), then he needs do 3 math operations:
1) take cubic root from mass X
2) raise to the second power result from previous step
3) multiply result and sq.mm for 1 ct.
just it. You can order such simple software and publish it. good luck

or you can do it yourself in Excel

 

[ChunkyCushionLover]

Date: 4/18/2010 12:54:47 AM
Author: Serg
CCl,
re;Serg,


It doesn''t do a consumer much good to know its 1.05 + 0.1=1.15 Carat and the other one is 1.5ct - 0.1 = 1.4 carats.
How much bigger is the 1.5 to the 1.05 in surface area difference?

1) 1.5 ct round has in 1.8 times bigger price than 1.05 ct round. This is very important and helpful information for consumer
2) 43sq.mm is clear bigger than 33 sq.mm . But is bigger enough or big enough ?,consumer can not decide by numbers in sq. mm. He needs see diamonds and compare. In such case it is very easy compare without any spread

Or about 25% bigger which is something they might want to know.

a) 1.05 ct round has bigger price then 1.02ct round on 3%, what is again important information for consumer( is big or small difference depends from consumer only and he can decide )
b) if difference in mass 3%, difference in sq mm is 2%. how is helpful information : first diamond has 34 sq mm , second diamond has 33.4 sq mm? It gives information just what first diamond is bigger. But anybody know what 1.05 ct round is bigger than 1.02 ct round( same proportions). Where is any additional information what sq.mm gives?

No they probably will have different cuts you can''t say that is always true, the 1.02 could faceup larger depending on the cut. Looking at the spread in carats of both will tell you if its true.

even beginner software developer can create for you simple software which recalculate mass of round diamond to sq mm.
you need just inform him about diameter for 1ct round cut( or sq. mm for 1ct round), then he needs do 3 math operations:
1) take cubic root from mass X
2) raise to the second power result from previous step
3) multiply result and sq.mm for 1 ct.
just it. You can order such simple software and publish it. good luck

I know you think every calculation is trivial, personally I can use Excel, or have my developer do this in a couple of minutes, but this is for Pricescope. You can put all of this information in a rollover or legend.

 

[Garry H (Cut Nut)]

Date: 4/19/2010 11:26:57 AM
Author: ChunkyCushionLover

Date: 4/18/2010 12:54:47 AM
Author: Serg
CCl,
re;Serg,


It doesn''t do a consumer much good to know its 1.05 + 0.1=1.15 Carat and the other one is 1.5ct - 0.1 = 1.4 carats.
How much bigger is the 1.5 to the 1.05 in surface area difference?

1) 1.5 ct round has in 1.8 times bigger price than 1.05 ct round. This is very important and helpful information for consumer
2) 43sq.mm is clear bigger than 33 sq.mm . But is bigger enough or big enough ?,consumer can not decide by numbers in sq. mm. He needs see diamonds and compare. In such case it is very easy compare without any spread

Or about 25% bigger which is something they might want to know.
And - More than twice the price - so what use is that knowledge?

a) 1.05 ct round has bigger price then 1.02ct round on 3%, what is again important information for consumer( is big or small difference depends from consumer only and he can decide )
b) if difference in mass 3%, difference in sq mm is 2%. how is helpful information : first diamond has 34 sq mm , second diamond has 33.4 sq mm? It gives information just what first diamond is bigger. But anybody know what 1.05 ct round is bigger than 1.02 ct round( same proportions). Where is any additional information what sq.mm gives?

No they probably will have different cuts you can''t say that is always true, the 1.02 could faceup larger depending on the cut. Looking at the spread in carats of both will tell you if its true. CCL you totally missed the point - I think if you understand this mistake in your thinking, you will agree with us?

even beginner software developer can create for you simple software which recalculate mass of round diamond to sq mm.
you need just inform him about diameter for 1ct round cut( or sq. mm for 1ct round), then he needs do 3 math operations:
1) take cubic root from mass X
2) raise to the second power result from previous step
3) multiply result and sq.mm for 1 ct.
just it. You can order such simple software and publish it. good luck

I know you think every calculation is trivial, personally I can use Excel, or have my developer do this in a couple of minutes, but this is for Pricescope. You can put all of this information in a rollover or legend.

 

[ChunkyCushionLover]

Date: 4/19/2010 4:42:51 PM
Author: Garry H (Cut Nut)

Date: 4/19/2010 11:26:57 AM
Author: ChunkyCushionLover

Date: 4/18/2010 12:54:47 AM
Author: Serg
CCl,
re;Serg,


It doesn''t do a consumer much good to know its 1.05 + 0.1=1.15 Carat and the other one is 1.5ct - 0.1 = 1.4 carats.
How much bigger is the 1.5 to the 1.05 in surface area difference?

1) 1.5 ct round has in 1.8 times bigger price than 1.05 ct round. This is very important and helpful information for consumer
2) 43sq.mm is clear bigger than 33 sq.mm . But is bigger enough or big enough ?,consumer can not decide by numbers in sq. mm. He needs see diamonds and compare. In such case it is very easy compare without any spread

Or about 25% bigger which is something they might want to know.
And - More than twice the price - so what use is that knowledge?

Gary I really appreciate the tools you and Serg have provided us with, if you don''t want to make it a little easier for consumers to get the information they want on size comparisons using surface area than okay, just use a thorough explanation of how spread is calculated in the rollover and how the consumer can get the size difference if they want it. I could provide more reasonable examples where similarly priced stones have different spreads by 0.1 carats but I think you have already made up your mind.

a) 1.05 ct round has bigger price then 1.02ct round on 3%, what is again important information for consumer( is big or small difference depends from consumer only and he can decide )
b) if difference in mass 3%, difference in sq mm is 2%. how is helpful information : first diamond has 34 sq mm , second diamond has 33.4 sq mm? It gives information just what first diamond is bigger. But anybody know what 1.05 ct round is bigger than 1.02 ct round( same proportions). Where is any additional information what sq.mm gives?

No they probably will have different cuts you can''t say that is always true, the 1.02 could faceup larger depending on the cut. Looking at the spread in carats of both will tell you if its true. CCL you totally missed the point - I think if you understand this mistake in your thinking, you will agree with us?

Not sure what that mistake is, what I see in this thread is explanations of calculation methods that can be used to get the information I asked you to provide directly in Diamcalc and in the PS search. I respect your opinion and that you will make reasonable changes to the in house listings at your discretion. I think we have beaten this topic to death at this point. Even spread in carats is significantly better than comparing depth % as many are doing now, hopefully this will also be added to the regular listings.

even beginner software developer can create for you simple software which recalculate mass of round diamond to sq mm.
you need just inform him about diameter for 1ct round cut( or sq. mm for 1ct round), then he needs do 3 math operations:
1) take cubic root from mass X
2) raise to the second power result from previous step
3) multiply result and sq.mm for 1 ct.
just it. You can order such simple software and publish it. good luck

I know you think every calculation is trivial, personally I can use Excel, or have my developer do this in a couple of minutes, but this is for Pricescope. You can put all of this information in a rollover or legend.

 

[Garry H (Cut Nut)]

CCL I hope it is a constructive discussion / debate.
I have been trying to understand you point of view.

The rollover is important.
And it can have a link to the spread page in it (I hope).

Any suggestions for an example? Perhaps a princess cut example where table and depth % are bad guides to spread?