Analysis without angles or images?

[iheartbora]

What kind of meaningful analysis can you do with only the following information? Is it possible to narrow down a list of 100 diamonds to a manageable list of maybe 5? If so, how? I''d love to use the HCA as a diamond rejection tool but we don''t have the crown and pavilion angles yet. I''ve tried to use the following information and narrowed down the list to about 15, all with similar 4C, triple Ex and price range, but I''m finding it really hard to further filter the list!!

- 4Cs
- Table size
- Depth
- Polish
- Symmetry
- Measurement
- Fluorescence
- Price

Thanks in advance!!

 

[Ellen]

You''ve really got to have the angles. The rest could fall in perfect ranges, but without the angles, it''s meaningless. Sorry.

 

[Lorelei]

Date: 4/27/2009 11:20:14 AM
Author: Ellen
You''ve really got to have the angles. The rest could fall in perfect ranges, but without the angles, it''s meaningless. Sorry.

Ditto. The angles are critical.

 

[oldminer]

You can take a different approach without the angles and instead use the percentages. Both come from the same set of measurements anyway and each can be calculated from the other, too. The HCA was set up for use of angles over prercentages, but Garry could have made it work better with percentages. It was his choice and based on how the diamond measuring scanners available then produced better angle measures than percentage measures. Most of that does not even apply these days. However, without percentages or angles, you are in sort of a lost zone for screening round diamonds. If you were looking at other shapes, the percentages would rule as angles don't work on most fancy shapes.

To screen further without percentages and anlges, you would need girdle thicknesses, minimum and maximum, any comments on painting-digging, any clarity plot comments that are not plotted, and culet sizes. It won't help a great deal, but you could well avoid overly thick or thin girdles, more than smal culets, and stones with caution comments. Since you have found so many, why not weed out several more?

You could eliminate any without images, too, and still have many to select from which look "right"

 

[iheartbora]

Date: 4/27/2009 11:31:23 AM
Author: oldminer
You can take a different approach without the angles and instead use the percentages. Both come from the same set of measurements anyway and each can be calculated from the other, too. The HCA was set up for use of angles over prercentages, but Garry could have made it work better with percentages. It was his choice and based on how the diamond measuring scanners available then produced better angle measures than percentage measures. Most of that does not even apply these days. However, without percentages or angles, you are in sort of a lost zone for screening round diamonds. If you were looking at other shapes, the percentages would rule as angles don''t work on most fancy shapes.


To screen further without percentages and anlges, you would need girdle thicknesses, minimum and maximum, any comments on painting-digging, any clarity plot comments that are not plotted, and culet sizes. It won''t help a great deal, but you could well avoid overly thick or thin girdles, more than smal culets, and stones with caution comments. Since you have found so many, why not weed out several more?


You could eliminate any without images, too, and still have many to select from which look ''right''

Thanks for the replies! I figured it''s quite hard to eliminate without percentages and angles, and looks like I''m right. I have no other info on hand (clarity plot, girdle, etc), but the vendor did confirm they are all H&A stones.

Another question... if all specs are the same (F colour, VS2, triple Ex GIA graded stone) except for little variations in the carat size (ie. 1.04 vs 1.0, but the price per carat is more expensive for the smaller stone, is it safe to "assume" that cut is the main factor that is driving the price higher vs. lower??

 

[stone-cold11]

Date: 4/27/2009 12:21:12 PM
Author: iheartbora
Another question... if all specs are the same (F colour, VS2, triple Ex GIA graded stone) except for little variations in the carat size (ie. 1.04 vs 1.0, but the price per carat is more expensive for the smaller stone, is it safe to 'assume' that cut is the main factor that is driving the price higher vs. lower??

Not that simple, the stones could have been cut before the economy really got hit hard, the price are priced then making them more expensive.

Why can't the vendor just give you the report numbers? Then it is not that difficult to look up the numbers online.

 

[Lorelei]

Date: 4/27/2009 12:21:12 PM
Author: iheartbora

Date: 4/27/2009 11:31:23 AM
Author: oldminer
You can take a different approach without the angles and instead use the percentages. Both come from the same set of measurements anyway and each can be calculated from the other, too. The HCA was set up for use of angles over prercentages, but Garry could have made it work better with percentages. It was his choice and based on how the diamond measuring scanners available then produced better angle measures than percentage measures. Most of that does not even apply these days. However, without percentages or angles, you are in sort of a lost zone for screening round diamonds. If you were looking at other shapes, the percentages would rule as angles don''t work on most fancy shapes.


To screen further without percentages and anlges, you would need girdle thicknesses, minimum and maximum, any comments on painting-digging, any clarity plot comments that are not plotted, and culet sizes. It won''t help a great deal, but you could well avoid overly thick or thin girdles, more than smal culets, and stones with caution comments. Since you have found so many, why not weed out several more?


You could eliminate any without images, too, and still have many to select from which look ''right''

Thanks for the replies! I figured it''s quite hard to eliminate without percentages and angles, and looks like I''m right. I have no other info on hand (clarity plot, girdle, etc), but the vendor did confirm they are all H&A stones.

Another question... if all specs are the same (F colour, VS2, triple Ex GIA graded stone) except for little variations in the carat size (ie. 1.04 vs 1.0, but the price per carat is more expensive for the smaller stone, is it safe to ''assume'' that cut is the main factor that is driving the price higher vs. lower??

Not necessarily as there are many factors that can affect pricing and it is only speculation as to why they are priced thus.

 

[jet2ks]

Date: 4/27/2009 12:21:12 PM
Author: iheartbora


Thanks for the replies! I figured it''s quite hard to eliminate without percentages and angles, and looks like I''m right. I have no other info on hand (clarity plot, girdle, etc), but the vendor did confirm they are all H&A stones.

Another question... if all specs are the same (F colour, VS2, triple Ex GIA graded stone) except for little variations in the carat size (ie. 1.04 vs 1.0, but the price per carat is more expensive for the smaller stone, is it safe to ''assume'' that cut is the main factor that is driving the price higher vs. lower??

Is this a huge question mark for anyone else? How can a vendor tell you the stones are H&A without images to prove it?!?!?!?

If they are going to say the stones are H&A, they should be able to provide both hearts and arrows images. They haven''t even provided angles, so that would raise several questions in my mind.

 

[oldminer]

The asking price of various diamonds which are all nearly the same, closely graded and about the same weight are often widely different for no apparent reason. Each diamond makes its own way through the supply chain. No two diamonds cost exactly the same to produce and the business is not like a commoodity where any can substitute for any other. There are similarities, but diamonds reamin individuals. The more costly diamond of two which are quite alike, may not be the more valuable.

 

[iheartbora]

Date: 4/27/2009 12:49:26 PM
Author: jet2ks

Date: 4/27/2009 12:21:12 PM

Author: iheartbora



Thanks for the replies! I figured it''s quite hard to eliminate without percentages and angles, and looks like I''m right. I have no other info on hand (clarity plot, girdle, etc), but the vendor did confirm they are all H&A stones.


Another question... if all specs are the same (F colour, VS2, triple Ex GIA graded stone) except for little variations in the carat size (ie. 1.04 vs 1.0, but the price per carat is more expensive for the smaller stone, is it safe to ''assume'' that cut is the main factor that is driving the price higher vs. lower??

Is this a huge question mark for anyone else? How can a vendor tell you the stones are H&A without images to prove it?!?!?!?


If they are going to say the stones are H&A, they should be able to provide both hearts and arrows images. They haven''t even provided angles, so that would raise several questions in my mind.

They don''t have the inventory on hand (drop ship vendor) that''s why I can''t get more info unless I narrow it down into a manageable list. The vendor does deal mostly with H&A stones.... but yea, I''ll believe it when I see it (with PS help of course)!