hearts view, what is this?

[Christina...]

I was recently doing a search for another forum member and I came across this stone. When I viewed the hearts image, you can see a dotted circle through the hearts pattern. I don't think that I have seen this before and I assume that it is the tiny triangles (sorry I have no idea if there is a proper name) on either side of the arrows on the star facets. I'm wondering though if it is somehow indicative of the stone potential performance, or if it means nothing....

ETA I think that I remember reading that these tiny triangle areas will produce areas of nice fire, is this true?

 

[04diamond<3]

I could be wrong but it looks like inclusions...I doubt it'll affect the performance of the diamond. But I've seen a number of EGL certified stones that show a pattern like this of inclusions...Those triangles are there regardless. I'm pretty sure it's just inclusions on the underside of the stone. What is the stone graded? Did you ask the gemologist? What does the report look like?

 

[Christina...]

Thanks O4diamond! The stone isn't for me, it was one that I came across during a search for someone else, but the clarity grade is a VS2 so I don't think that it's inclusions. The only obvious one was a crystal in the table that can be seen in the actual diamond photo. I'll link the stone, maybe that will be more helpful.

http://www.jamesallen.com/diamonds/J-VS2-Ideal-Cut-Round-Diamond-1542001.asp

 

[04diamond<3]

I'm still thinking it's inclusions. It is odd that it's not on the report and can't see it on their website other than on the hearts image. I chatted them and they were extremely difficult to talk to (i bet because I wasn't the one buying). They said that they'd ask the gemologist but you'd have to give them your info and wait 2-3 business days.

 

[04diamond<3]

those "triangles" are on all the other ideal cut and h&a stones:

http://www.jamesallen.com/diamonds/H-VVS2-Ideal-Cut-Round-Diamond-1527053.asp

And I found another one that has the same thing:

http://www.jamesallen.com/diamonds/I-SI1-Ideal-Cut-Round-Diamond-1458708.asp

It also doesn't show up on the AGS report....THAT is definitely odd. I wonder why. Maybe because it's not possible to see them? That's still not fair grading...if you look on this one, you can see the circle of inclusions with the magnifying glass I suppose it's easier because the .78 stone picture is a smidge zoomed in compared to the .46, but I bet it's the same thing. Still annoyed that AGS isn't putting these on the report.

 

[John P]

Hello.

In both stones you're seeing reflections of a center-located crystal. The central position and elevation causes the symmetrical reflection in the first. In the second the crystal is slightly off-center, with resultant asymmetrical reflections.

...I'm still thinking it's inclusions. It is odd that it's not on the report and can't see it on their website other than on the hearts image. I chatted them...

The crystal in each diamond does appear in the clarity plot. Inclusions are plotted only once; reflections are not plotted. Someone with the diamond in-hand can tell you if the reflections are visible face-up. The hearts view exaggerates such things so it's both useful to have ("okay, there's a reflective crystal here...") but can show reflections where non are actually visible IRL.

those "triangles" are on all the other ideal cut and h&a stones:

They can be. The triangles (they have been nicknamed "watermelon seeds" here in past years) are secondary reflections of the obstructed pavilion mains appearing under the bezels. Whether you see them depends on a number of things including - in particular - camera lens position and degree of obstruction, as well as the angular particulars of the faceting.

 

[04diamond<3]

huh, that's interesting! Didn't know crystals could do that...I've seen EGL reports that have this type of circle as inclusions on their reports...very odd.

 

[Christina...]

Hello.

In both stones you're seeing reflections of a center-located crystal. The central position and elevation causes the symmetrical reflection in the first. In the second the crystal is slightly off-center, with resultant asymmetrical reflections.

...I'm still thinking it's inclusions. It is odd that it's not on the report and can't see it on their website other than on the hearts image. I chatted them...

The crystal in each diamond does appear in the clarity plot. Inclusions are plotted only once; reflections are not plotted. Someone with the diamond in-hand can tell you if the reflections are visible face-up. The hearts view exaggerates such things so it's both useful to have ("okay, there's a reflective crystal here...") but can show reflections where non are actually visible IRL.

those "triangles" are on all the other ideal cut and h&a stones:

They can be. The triangles (they have been nicknamed "watermelon seeds" here in past years) are secondary reflections of the obstructed pavilion mains appearing under the bezels. Whether you see them depends on a number of things including - in particular - camera lens position and degree of obstruction, as well as the angular particulars of the faceting.

Huh! That's interesting John, thank you. So it's possible that this single inclusion could be seen repeatedly in the face up position? That would be a downer in a VS2! Have you seen this happen IRL were a single inclusion is repeated and eye visible?

One more question, I think that I've heard that the 'watermelon seeds' can potentially be areas of nice colored light return. Am I remembering that correctly?

 

[John P]

Huh! That's interesting John, thank you. So it's possible that this single inclusion could be seen repeatedly in the face up position? That would be a downer in a VS2! Have you seen this happen IRL were a single inclusion is repeated and eye visible?

You're very welcome.

Reflecting inclusions can appear to the naked eye, but not usually in VS+ diamonds. Logically, they're easier to see in larger diamonds when the inclusion is prominent and is centered.

I don't see anything in the virtual loupe photos that indicates any kind of face-up influence in these diamonds. The dynamic only occurs in the hearts images, which were taken face-down. At 0.46 and 0.78ct I wouldn't expect them to be visible anyway, even if "something" was noticeable in the virtual loupe.

One more question, I think that I've heard that the 'watermelon seeds' can potentially be areas of nice colored light return. Am I remembering that correctly?

Yes, because they're reflections of the pavilion mains which drive primary light return. Here's a quick explanation:

* The leftmost photo below shows the facet structure of a modern RB.
* The center photo shows the pattern of single reflection. Note the arrowheads and "seeds" are both pavilion main reflections.
* The right photo highlights the seeds (which are, technically, secondary reflections of the mains).


In the static diamond photos you're used to seeing the mains are obstructed. By following the obstruction pattern we can follow where the light striking the mains travels once the diamond is in "the real world" and in-motion.

* The leftmost photo below shows the pavilion mains obstructed with no reflection.
* The center photo highlights single reflection in gold - the arrowheads and seeds appear.
* The right photo adds the pattern of double reflection (purple) which brings "table reflection" into the picture.

Table reflection occurs because main obstruction is "seen" by the underside of the table, reflected down, and then reflects up yet again (double reflection) in the pavilion of the diamond.

I hope this is interesting.

 

[kenny]

If you buy those diamonds please do not have them set up side down.

 

[Christina...]

Thanks John, it was very interesting. Can I ask one more question? At what weight would you be more likely to see this reflection? Over a ct? 2ct? And I'm assuming more so in SI and lower clarity? Would it always be wise to request arrow images if the stone in question has a table centered inclusion? Okay so that was more than one question. Appreciate all the information, it's been really informative!

 

[Christina...]

If you buy those diamonds please do not have them set up side down.

check out this upside down goodness!! RDG

 

[Dancing Fire]

my wife's H&A stone looks identical to your pic. the single dark crystal under the table is reflecting against the facets. IRL i can't see the inclusion because my pair of eyes is very old...

 

[John P]

Thanks John, it was very interesting. Can I ask one more question? At what weight would you be more likely to see this reflection? Over a ct? 2ct? And I'm assuming more so in SI and lower clarity? Would it always be wise to request arrow images if the stone in question has a table centered inclusion? Okay so that was more than one question. Appreciate all the information, it's been really informative!

Christina,

You're welcome. Good follow-up questions...

RE Visibility: You may never see them face-up, regardless of size. The hearts view is taken with the diamond upside-down, so what you're seeing is in the underside of the crown facets. Their presence is exaggerated in the H&A viewer as it's a structured light environment designed to illuminate patterning anomalies. Hypothetically, if we expand this diamond to 10 carats and increase the relief (darkness) of the inclusion enough we will be able to see it in the pavilion with the naked eye. Whether it would have influence face-up I can't say without examining the diamond in-person.

RE SI and lower clarity: As a rule, yes. Of course it always depends on the specific diamond - and the entity which assigned the grade.

RE: Requesting arrows image: I always like to have the arrows but in this case Ideal-Scope, ASET and H&A viewers exaggerate light path anomalies. That is their purpose. Since the H&A viewer uses stark white light, top-down, it tends to illuminate characteristics in those areas even more than the other viewers. I'd say the magnified/loupe view should generally be considered the most realistic, and even that is magnified where we'll see inclusions in a photo we may never see IRL.

With that said, a flat 2D view is always going to have limitations. "Magnified" photos are frequently taken in such a way that some inclusions are rendered less-visible than other. This is a function of focal depth and aperture settings. When we grade diamonds in the lab we use a microscope to "descend" focally through the diamond to identify and plot inclusions. When those inclusions are at different depths it's often the case that the one at the depth we're looking-at is sharp, whereas those at other depths have become less visible or invisible. A good photographer will compensate for this when working carefully, but the greater the depth-of-field the less-sharp the overall details become. This is nothing malicious, I say this as an umbrella over the limitations of photo interpretation from the buying side of the counter.

At the end of the day this is another area where only a gemologist with the diamond in-hand can give decisive answers. There are clues - like a central characteristic with high relief potential - but whether an inclusion reflects is another question to put on the clarity list ~ along with level of eye-clean, the influence of clouds as primaries in SI, a clarity grade based on XYZ "not shown," implications of feathers or naifs, etc.