Extra Facet question (GIA screenshot)

[teklit]

Hello folks!

I'm trying to purchase a loose diamond online.
After entering my economical values into the diamond filtering mechanism (cut my priority- table and depth % in excellent range), I found something interesting that falls in my budget. This gem is higher in color and clarity than the others I can afford.



This piece is 1.72 ct, F-color, VS-1. I believe the reason I was able to find this is because of the extra facet on the pavilion, it also has a 1.3 l/w ratio which I don't mind. Another difference, the facet diagram on the GIA report is not the same as the other oval facet diagrams I've been viewing.

So my question is, how will the Extra Facet on the pavilion affect the light performance of the diamond?

Furthermore, if anyone could explain why the facet cut diagram is different, that'd be great. I'm sure I could figure it out but I haven't tried searching just quite yet.


Here is an example of the facet cut diagrams that normally show up.




Thank you

teklit

 

[WinkHPD]

I am NOT an oval specialist, so I will not make any guesses as to the facet pattern on your diamond grading report versus others that you have been looking at.

As for the extra facets shown at the approximate 11 0'clock area.

These should have very minimal affect on the eye visible light return to your eye. You might need an ASET image to determine this exactly, but you can also look at one end of the oval without the extra facets and the other with and see if you see anything that bothers you.

I would ask the vendor what he sees with his eyes. I would also ask the vendor about what I do expect you to be able to see, the existence of or the absence of a bow tie. That is FAR MORE likely to affect your enjoyment of this diamond.

Wink

 

[tyty333]

Do you have this stone reserved? Can you provide a link?

Or if not, can you post an up close picture of the stone.

There are a few different oval faceting patterns. I dont think the pattern itself affects the price that much. The price would be
more driven by how well the faceting pattern is cut and how well it reflects light (besides color & clarity).

Ovals...look for
- minimal bow-tie
- nice feathered faceting pattern between any bow-tie and ends of oval
- no shoulders
- nice length to width ratio
- decent aset image

 

[teklit]

After reading your posts, and doing a bit of googling, I found tons of comments about how common bow-ties are in oval cuts.
I do not have it reserved, nor do I have any extra pictures of any kind. Not sure if this vendor offers pictures upon request, and I'm not quite ready to take that step as I have a lot more learnin' to do.

Not set on having an Oval, I just searched it to see what else my money could buy in fancy cuts I find appealing and found this extremely interesting.

Thank you for sharing your knowledge.


teklit

 

[tyty333]

Ok, well then, let me add that you can not buy fancy cut stones (that would be anything besides a round brilliant) without images.
There are just too many variables in fancy cut stones.

My choice for vendors for ovals would be JA.
www.jamesallen.com because they have videos of their stones so you can see how they reflect/react as they move. They also
offer aset images of stones local to them. You can request up to 3. Get help from PS before requesting anything because we
can eliminate bad performers without them (usually).

For princess cut stones you could do AGS000 stones which you can get at Whiteflash and Brian Gavin Diamonds.

We also have favorite vendors for cushions...GOG, Brilliantly Engaged
GOG will also bring in some ovals and video for you (I think there is a fee).

Old stones like OECs or OMCs...Love Affair Diamonds, Jewels by Grace and Old World Diamonds.

Anything else would be James Allen. JA is always a good place to start (except for OECs or OMCs).

Have fun learning! And let us know if/when you need help.

 

[tyty333]

Oh, and just to point out what some nice ovals look like (just for an example...)

http://www.jamesallen.com/loose-diamonds/oval-cut/2.01-carat-f-color-vs1-clarity-sku-302720
http://www.jamesallen.com/loose-diamonds/oval-cut/2.00-carat-g-color-vvs2-clarity-sku-374559
http://www.jamesallen.com/loose-diamonds/oval-cut/1.01-carat-d-color-vs2-clarity-sku-606287

The following have nice faceting pattern but not sure about the light return...an aset would show whats going on
http://www.jamesallen.com/loose-diamonds/oval-cut/1.02-carat-f-color-si1-clarity-sku-536815
http://www.jamesallen.com/loose-diamonds/oval-cut/1.01-carat-g-color-vs1-clarity-sku-587037
http://www.jamesallen.com/loose-diamonds/oval-cut/1.02-carat-g-color-vvs2-clarity-sku-373919
http://www.jamesallen.com/loose-diamonds/oval-cut/0.90-carat-f-color-vs2-clarity-sku-373924 this is one of those different
patterns...as you can see it has no bow-tie but the light return looks only so-so

 

[teklit]

thanks for the info, tyty333, that was very generous of you.
I've been looking into everything you talked about.

If you don't mind helping me train my eye...
In the vid links, what is cluing you in that the top 3 have better light return?
After staring at them for some time, I can only make a guess. Is it the virtual facets (is that the right term?) inside the stones, the top three have more?

 

[oldminer]

I know you said a ratio of 1.3:1 does not bother you, but a shape of that ratio is sort of roundish and may not command the highest level of value. WIth a relatively short length to width ratio, one might find less visibility of a bow tie since as a diamond approaches a round shape, the bow tie naturally decreases.

The extra facet likely won't have any big effect, if any, as you have been told. The girdle thickness, and crown height all play into how the diamond will perform, and we don't know if you considered all the relevant screening parameters. Table and depth don't begin to do justice to what can be done by screening properly. Also, what is the symmetry grade?

The wire frame clarity plot depepiction which matches the facet pattern of this particular diamond is the one used by GIA. There are several variations that can be used. The plot facet lines show this stone to have a particular layout of facets that can work just fine, but are not like many other ovals which are laid out a bit differntly on the crown and on the pavilion. Again, I doubt much difference in value will occur because of this facet arrangement.

 

[teklit]

Thanks Oldminer,

Yes, if I was given the choice of two oval diamonds on either side of the ratio spectrum, assuming both equally beautiful, I'd definitely pick the fat one. While checking out ratio shape examples, I didn't really like any of the ovals over 1.6

I bookmarked this diamond. Looking at the GIA report I found another flaw that brings the price down and could possibly make this F diamond eye-ugly, it's fluorescence is strong.

Girdle thickness is medium to thick.

No crown or pavilion angle/height listed. (I read that's normal for oval GIA reports)

Symmetry very good.

Polish excellent.

Cut very good.



One more question, tyty333 said to look for an oval without shoulders. What exactly does that mean?

 

[teklit]

Oops, one more question. About how much would you figure it'd cost the consumer to have a jeweler pull a diamond from warehouse and inspect it with aset?