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Connection between IS and Optical Symmetry...

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DiceKTak

Rough_Rock
Joined
Feb 18, 2010
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Does the idealscope tell us anything about optical symmetry? Can I use it to determine the likelihood that I will observe a face up arrows pattern in a diamond? This particular diamond is not H&A, but I''d assume I will see relatively well defined arrows face up, no? Is it possible to not see patterning if the symmetry of the IS is decent or am I mis-extending this technology? What is the minimum degree of face up patterning I can expect based on an idealscope alone? Or do I need a hearts and arrows viewer to figure this out.

ISOptics.jpg
 
If you said you''d expect some face up arrows, how would this Hearts Viewer effect that assessment? Degree of patterning assumption still valid?

HAOpitcs.jpg
 
Any thoughts?
 
Date: 2/23/2010 11:11:03 PM
Author:DiceKTak
Does the idealscope tell us anything about optical symmetry? Can I use it to determine the likelihood that I will observe a face up arrows pattern in a diamond? This particular diamond is not H&A, but I'd assume I will see relatively well defined arrows face up, no? Is it possible to not see patterning if the symmetry of the IS is decent or am I mis-extending this technology? What is the minimum degree of face up patterning I can expect based on an idealscope alone? Or do I need a hearts and arrows viewer to figure this out.
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Hi Dice

You need actual idealscope and hearts images rather than computer generated images in order to evaluate cut precision and optical symmetry. The IS can give you good information concerning optical symmetry yes but really hearts images are needed for a proper evaluation of overall cut precision, but an IS image will give you a decent idea of face up patterning. Many well cut stones that aren't h&a can show well defined arrows.

This tutorial explains more about cut precision

Interesting link on h&a diamonds which includes useful information on optical symmetry/ cut precision,

http://journal.pricescope.com/Articles/65/1/Hearts-and-Arrows-Diamonds-and-The-Basics-of-Diamond-Cutting.aspx
 
Download the gem adviser file and the viewer from one of the GOG stones and play with it.

You can select the orientation of the stone and lighting conditions to view the stone in, in this case IS and normal lighting conditions. Then you will get your answer.

For face up arrows, IS is good enough, which is one of the reasons vendors rarely post arrows image from a H&A viewer.
 
Thanks for the answers...

If this were a continuum from IDEAL CUT (NO PATTERNING) H&A, Perfect Patterning, how much confidence would you have from an IS image (or DiamCalc generated IS image) alone to say that this stone is closer to one end than the other?

From these images, would someone be able to be confident in claimining that this stone is closer to H&A (the diamond on the right in the GOG link) and not patterned (the diamond on the left in the GOG link).
 
Thanks Dice. This thread has helped explain what you meant earlier a bunch. I think I see what you mean now.
 
I''m not sure what you mean by "ideal cut no patterning"... does that exist?

In my experience you can see the arrow patterns using any type of dark colored magnification tool, since they reflect dark back to the eye. If all you care about is arrows and pleasant face up patterning, then the IS is fine for that. But as other mentioned, true hearts images are needed to determine ultimate precision/

Chase are you using two PS names?
 
Date: 2/24/2010 10:24:49 PM
Author: dreamer_dachsie
I''m not sure what you mean by ''ideal cut no patterning''... does that exist?
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Hmm.. just looked at the GOG link. We don''t see many of the no-pattern types on PS. If they are common in the AGS0 or GIA Ex ranges then why don''t they pop up more?
 
3, to avoid lurking LIW who has access to my comp... shh.
 
Well thats just the thing. I see patterning as a continuum and I haven''t decided yet how far down the continuum (away from H&A) I''m willing to go to stick to a budget. I know I thoroughly enjoy her promise ring, and its hard to make out the arrows in that ring (but they''re visible, to some degree).
 
Date: 2/24/2010 10:36:35 PM
Author: Chase035
Well thats just the thing. I see patterning as a continuum and I haven''t decided yet how far down the continuum (away from H&A) I''m willing to go to stick to a budget. I know I thoroughly enjoy her promise ring, and its hard to make out the arrows in that ring (but they''re visible, to some degree).
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I have owned a few H&A diamonds, and I have owned a non H&A diamond that was a patterned ideal cut which I chose aided by my IS and a loupe. Both looked good to me. I think the subtle differences in cut quality becomes more apparent when you move towards larger diamonds because the virtual facets become larger and so the way your eye perceives the optics becomes more apparent. When I went from a .80 to a 1.2ct diamond, the difference in appearance of the facets and arrows was marked to me. I personally would stick with a non-H&A ideal cut patterend stone to optimize budget and maintain the organized appearance of a symmetrical cut. Also consider whether dropping to a non-patterned H&A would actually buy you a lot of size anyways. The price jump at 1ct and 1.5ct is so large that even dropping to a non-patterend cut would probably not get you over that hump unles you had the funds to buy the H&A diamond anyways!
3.gif
make sense?

What size are you considering?
 
She said she''d like .5 (she has small hands and thought anything bigger was unnecessary). I convinced her .75 would not look too big. So somewhere between there. Desired specs are on here, under third log-in.
 
Date: 2/24/2010 10:57:15 PM
Author: Chase035
She said she''d like .5 (she has small hands and thought anything bigger was unnecessary). I convinced her .75 would not look too big. So somewhere between there. Desired specs are on here, under third log-in.
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Its too sleuthy for me to find it...
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In that size you can go non H&A with no worries at all in my opinion. Perhaps even find a nice VG GIA cut.
 
Thing is, H&A by itself tells you nothing about performance.


H&A simply means hearts and arrows are visible, perfect optical symmetry. You can have a perfect H&A stone that's lousy because the angles are all wrong for each other but the facets are still oriented the right way, the girdle is huge...


When you buy a H&A stone from a H&A vendor, then, you're not just getting a stone with perfect optical symmetry - you're getting a stone that fulfills all the other requirements of that vendor's brand of H&A (generally cherry proportions for a universal crowd-pleaser).


To get a stone that has great light return you don't need perfect optical symmetry, you just need those nice proportions. Often a gorgeous stone would not make any H&A line even if it did have gorgeous hearts because the angles, while good together, fall outside a certain range, but buying a branded H&A is a good way to ensure you're getting a fantastic, top of the line performer.


If that makes sense! So yes, in that size range, I would go with a non-H&A good performer to maximize budget.
 
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