Does AGS 000 = arrows pattern?

[milton333]

I''ve seen variants of this question asked, but I guess I''m still not sure of the answer - if a diamond gets an AGS 000 Ideal rating for light performance, will it, by default, have an arrows pattern? I understand that it still may not have the hearts pattern from the underside, because there is some additional precision involved, but does AGS 000 = an arrows pattern?

 

[Paul-Antwerp]

Not necessarily, no.

The contrast and the symmetry of a good H&A contribute most to scintillation. Since the study of scintillation is still a study, it is not an aspect of the current AGS-grade on light performance. Or should I say, not yet?

Live long,

 

[JohnQuixote]

Date: 12/13/2007 4:13:09 PM
Author: Paul-Antwerp

Or should I say, not yet?

Exactly.

'Arrows' are just the pavilion mains, seen through the diamond's table. Since all rounds have these mains someone could answer 'yes' Milton, but only if they permit some sloppy examples. Cut precision is not currently measured by the labs.

See the attached graphic: When 2 pavilion mains opposite each other are precisely cut the facet reflections 'overlap.' This effect is most clear in overhead/crown photos where obstruction by the camera (or the viewer) reflects in the mains. The effort to cut a diamond to specific standards (like AGS0 or GIA EX) often results in crisper-than-average arrows. The level of crispness varies widely though.

Since no standards are enforced it is easy for a jeweler to say all diamonds have patterning effects, but it always depends on the specific stone and the motives of the person making the judgment: Someone wanting to sell average stones as "H&A" will say 'yes' much faster than those who work to respect & keep-exclusive the top level of H&A precision.

If you're interested in some history/importance, here is a thread with discussion and graphics. It has an AGS0 example that does not have such great arrows or hearts (by the standards of some). Logically you will not find such photos in abundance, because they are not taken. It doesn't serve a purpose for a seller to say "here is a photo showing how bad the hearts & arrows look in this diamond."

As a rule, diamonds with what top experts reward as H&A will have accompanying reflector photos of both crown and pavilion.
Diamonds that don't will not.

 

[Lynn B]

(As usual) GREAT post and graphics, John. THANKS!

I also re-read the thread in the link you posted. I remember it well.

*Happy sigh* It''s threads like these that I LOVE about PS!

Lynn

 

[milton333]

Thank you, John, that helps a lot.