Measurements

[Selly]

A few questions on measurements.

1. It seems to me that stones with smaller differences in diameters should be more symmetric (in proportion and optical properties) than similarly cut cuts with larger differences in diameters. For example, given other things being equal, shouldn''t a stone that is 6.54 mm x 6.56 mm (average 6.55 mm) be more symmetric than a stone that is 6.52 mm x 6.58 mm (again, average 6.55 mm)?

2. In using HCA, we enter average crown and pavillion angles. So, it seems to me that stones with a smaller range of angles should be more symmetric (again, in proportion and optical properties) than stones with a larger range of angles. For example, given other things being equal, shouldn''t a stone with crown angles of 34.6 - 34.8 (average 34.7) be more symmetric than a stone with crown angles of 34.3 - 35.1 (again, average 34.7).

3. Same question no. 2 with respect to pavillion angles.

4. The really big question - if the answer to any/all of the above is yes, i.e., that smaller ranges lead to more symmetry, does that make the diamond "better" in terms of performance, or better in any way?

Would appreciate any help since I''m a newbie and comtemplating the first serious purchase of my life.

Thanks,

Selly.

 

[oldminer]

Perfection is "better". Now, how much perfection will you pay for that is invisibly "better"? That is a very personal and subjective decision. Each person needs the facts, examines the stones and then decides.

 

[Paul-Antwerp]

Date: 9/21/2006 12:54:20 PM
Author:Selly
A few questions on measurements.

1. It seems to me that stones with smaller differences in diameters should be more symmetric (in proportion and optical properties) than similarly cut cuts with larger differences in diameters. For example, given other things being equal, shouldn''t a stone that is 6.54 mm x 6.56 mm (average 6.55 mm) be more symmetric than a stone that is 6.52 mm x 6.58 mm (again, average 6.55 mm)?

Great questions. On this first one, the answer is a qualified yes. Roundness and less variation in the diameter makes the life of a cutter easier. If he is then aiming for a very symmetrical cut, it will be easier with a more perfectly round diamond. But the fact of the stone being very round alone is no guarantee for more symmetry.

Date: 9/21/2006 12:54:20 PM
Author:Selly
2. In using HCA, we enter average crown and pavillion angles. So, it seems to me that stones with a smaller range of angles should be more symmetric (again, in proportion and optical properties) than stones with a larger range of angles. For example, given other things being equal, shouldn''t a stone with crown angles of 34.6 - 34.8 (average 34.7) be more symmetric than a stone with crown angles of 34.3 - 35.1 (again, average 34.7).

3. Same question no. 2 with respect to pavillion angles.

Yes. On both your questions. However, bear in mind that we are still only talking about 16 of the 57 facets.

Date: 9/21/2006 12:54:20 PM
Author:Selly
4. The really big question - if the answer to any/all of the above is yes, i.e., that smaller ranges lead to more symmetry, does that make the diamond ''better'' in terms of performance, or better in any way?

Yes, yes and a cheering yes again. However, I can only base this judgment on personal observation, and on the observation of consumers, who have described what they see in extremely symmetrical diamonds, be they round or princess-cuts. Unfortunately, most scientists have not performed any real studies up to this level. If we talk labs, GIA has limited its studies to the level of average proportions. AGS takes the full 3D-measurement into account in their light performance grading, but they have never released any info on the effect of the level of symmetry, that you are talking about. Unfortunately also, very few diamonds in the world are cut in this way, and there might be a statistical problem in the studies.

Hope that this info helped,

 

[Selly]

Thanks for all the info. I''m amazed by how much I''ve learned here in just a few days - I probably won''t spend any less than I had planned but will definitely get my money''s worth now. In the end, my ff will be the beneficiary of your expertise. Again, may thanks.