Help Need! How important is Depth?

[hubn]

I'm looking for a ring for my GF and haven't been doing too much research online. I'm trying to propose before the end of year so I don't have much time to research more anyway. Actually I haven't even saw any diamond yet and probably own't seen too much before I make the purchase online (to save cost). I do come up a few selection criteria though. The basis behind them is I want to get the biggest stone I can get that will fair well under the naked eye even with a relative close comparison.

Budget: 20k, you can see from the question below that i soon went over that
Cut: Ideal, from the limited research I done i got the feeling you shouldn't compromise on this unless you are really short on $$$
Carat: as big as possible
Color: F and above,
Clarity: VS1 above, I know VS2 are suppose to be eye clean as well but i'm a kind paranoid person so I want some buffer
Report: AGI, won't see any diamond in person so I will depend on good report and reputable company

I found two stone that i'm interested in
first one is
Cut: Ideal
Carat: 1.74
Color: F
Clarity: VS1
$$$: $21k
http://www.bluenile.com/diamond-search?track=hero#diamonds_pid=LD02218183

second one is
Cut: Ideal
Carat: 1.8
Color: E
Clarity: VS1
$$$: $22k
http://www.bluenile.com/diamond-search?track=hero#diamonds_pid=LD02357690

The second one is bigger (also being a Chinese, 1.74 is really a unlucky number so it influence the buy as well), whiter only for 1k more. The only drawback is the depth on the second one is 62.9% which is in the good categories. The depth of the other stone and the table of both stone are within the very good + categories.

My main questions is how important is depth. My concern is 62.9% is borderline fair/poor already. What's the downside of such a ring? Would appreciated the answer to be in my selection criteria, if I put it side to side to an identical ring with very good/ excellent depth, what would I observe (naked eye, without scope of course).

Also, any other comment on the stone including any other factor i'm missing and should be looking at or there is better deals on similar ring out there would be great appreciated as well.

 

[kenny]

Good cut is more important than clarity or color to the beauty of a diamond, how well it performs with light.
Fortunately there are two tools to help you find a well cut round diamond.
1. HCA https://www.pricescope.com/tools/hca
2. Idealscope https://www.pricescope.com/tools/ideal-scope

FIrst get these four numbers from the GIA or AGS report:
1. Depth %
2. Table %
3. Crown Angle in degrees.
4. Pavilion Angle in degrees

Plug them into the HCA and click on GO.
Reject diamonds that score over 2.0.

Get an idealscope pic on those that scored under 2.0.
Compare the pic to this chart:

 

[kenny]

Here's the first diamond's HCA score.
I'd reject it since it is over 2.0.
This diamond will not be returning as much light to your eyes as it would if it was a better cut.

 

[Dancing Fire]

i'd pass on both stones b/c they aren't well cut...

btw; you need to find a 1.88ct stone...

 

[kenny]

I'd also reject the second.

Both ARE too deep.
They cut them that way to save weight.

BTW, Bluenile refuses to provide Idealscope pics.

I'd shop at the following very reputable online vendors:
Good Old Gold.
Whiteflash
James Allen
Brian Gavin Diamonds
High Performance Diamonds

 

[hubn]

Just finished the calculation myself as well, both them scored badly. Good thing I asked here before I pull the trigger. Back to do more search.

 

[hubn]

does that mean this stone although is labeled only with Very Good cut in GIA report actually is better cut than the two stone I list above and are more worth buying?

http://www.bluenile.com/certs/2135167000.pdf?params=cHJvZHVjdD1CTiZwaG9uZT04ODgtNTY1LTc2NDEmbGluaz1odHRwJTNBJTJGJTJGd3d3LmJsdWVuaWxlLmNvbSUyRiUyRl9MRDAyMDYwMDE3JnNrdT1MRDAyMDYwMDE3JmxhYj1naWEmc2l6ZT0xNjAwJmN1cnJlbmN5PVVTRCY%3D

HCA score 0.9.

I know i can't get an idealscope from blue nile, but with cheapest comparable stone i found from the site listed are a stone at Brian Gavin Diamonds that cost ~2000 more after i applied all the discount, cash back i can found for blue niles. There isn't much for the other website.

My questions is that what's the chance an diamond will have a horrible idealscope while has a really nice hca score. Should I take a gamble on it(right now i'm leaning toward it since I don't quite understand how to real idealscope picture yet). Also, is there any local place that I can get take the ring to (After it's set already) and get an idealscope (with a fee of course) and then re-set it for me? Worst case i can return the ring to blue niles if the idealscope picture turn out to be awful.

 

[Gypsy]

There is a chance of it. HCA is a rejection tool, not a selection tool. Idealscope is a selection tool as it is an image of the light performance of your actual diamond (where as the HCA is just something that calculates the angles). If you want certainty on the idealscope you need to go with a vendor that can provide one pre-sale, and Blue Nile doesn't.

 

[kenny]

My questions is that what's the chance an diamond will have a horrible idealscope while has a really nice hca score.

Instead of speculating on the chances (I'm not a fan of gambling with $21,000) I'll go you one better.
I'll explain what the Idealscope pic reveals, which explains how it replaces gambling with certainty.

The GIA report gives only one number for the crown angle and one for the pavilion angle, even though a modern round brilliant diamond has 8 sides.
(There are actually 8 Crown angles and 8 pavilion angles.)

The one crown angle on the GIA report is the average of the eight sides.
The one pavilion angle on the GIA report is the average of the eight sides.
Averages can be deceptive.
A man with one hand in boiling water and the other hand frozen in ice is, on the average, quite comfortable.

That means all crown angles could be exactly the same (a good thing) or they could be very high and very low but average out to the perfect average (a bad thing).
Same for the pavilion angles.

The idealscope pic is an actual photograph of the actual diamond.
If the angles were all over the place or all very close to the average it will be obvious from the pic.

 

[diamondseeker2006]

I am afraid that you may have trouble a true ideal cut 1.7 F VS1 stone for the $20k. I did a quick search of AGS ideal cut stones on the search tool here and found prices as follows:


Carat Clr Clarity Depth Table Lab Cut Sym Pol Flr Measurements HnA HCA $/Carat Price Source
1.50 F VS1 61.7% 56% AGS 0 Ideal ID ID N 7.26x7.37x4.53 Y 1.2-EX $16746 $25120
1.54 F VS1 61.2% 56% AGS 0 Ideal ID ID N 7.42x7.45x4.55 Y 1.4-EX $17524 $27006
1.55 F VS1 61.6% 57% AGS 0 Ideal ID ID N 7.40x7.42x4.57 Y 0.9-EX $17081 $26493
1.55 F VS1 61.7% 55% AGS 0 Ideal ID ID N 7.43x7.46x4.59 Y 1.5-EX $16914 $26285
1.64 F VS1 62.2% 56% AGS 0 Ideal ID ID N 7.53x7.56x4.70 Y 1.4-EX $16713 $27410
1.74 F VS1 61.6% 56% AGS 0 Ideal ID ID N 7.70x7.73x4.75 Y 1.1-EX $17252 $29951

First and 5th stones are James Allen and the others are WhiteFlash. All are AGS ideal so they pass the HCA and you don't need to plug in your numbers. So you need to adjust the size, color, clarity, or budget before proceeding.

 

[diamondseeker2006]

Under $20k, here is what I can find in AGS Ideal cut, F VS1:

http://www.briangavindiamonds.com/diamonds/diamond-details/1.308-f-vs1-round-diamond-ags-104054185003

http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2684398.htm

 

[Dancing Fire]

I am afraid that you may have trouble a true ideal cut 1.7 F VS1 stone for the $20k. I did a quick search of AGS ideal cut stones on the search tool here and found prices as follows:


Carat Clr Clarity Depth Table Lab Cut Sym Pol Flr Measurements HnA HCA $/Carat Price Source
1.50 F VS1 61.7% 56% AGS 0 Ideal ID ID N 7.26x7.37x4.53 Y 1.2-EX $16746 $25120
1.54 F VS1 61.2% 56% AGS 0 Ideal ID ID N 7.42x7.45x4.55 Y 1.4-EX $17524 $27006
1.55 F VS1 61.6% 57% AGS 0 Ideal ID ID N 7.40x7.42x4.57 Y 0.9-EX $17081 $26493
1.55 F VS1 61.7% 55% AGS 0 Ideal ID ID N 7.43x7.46x4.59 Y 1.5-EX $16914 $26285
1.64 F VS1 62.2% 56% AGS 0 Ideal ID ID N 7.53x7.56x4.70 Y 1.4-EX $16713 $27410
1.74 F VS1 61.6% 56% AGS 0 Ideal ID ID N 7.70x7.73x4.75 Y 1.1-EX $17252 $29951

First and 5th stones are James Allen and the others are WhiteFlash. All are AGS ideal so they pass the HCA and you don't need to plug in your numbers. So you need to adjust the size, color, clarity, or budget before proceeding.

i don't think Chinese people will go for that #...

 

[hubn]

Thank you all for the help. It looks like my original criteria it too high since I didn't know anything about HCA. I'm thinking of lower my criteria here but are seeking some advise.

I really don't want to go down in size under a 1.5c since all of my friend bought their girl 1.5 above (i doubt they looked all the factor I'm looking here since I don't believe they spent more than my budge. but unfortunately, size is the first thing you notice. And I don't want to drop in clarity as well since you can starting to see the inclusion with naked eye below vs2. So I'm thinking of reduce the color selection as low as a H (from research, anything below is disaster). This will end me some good stone in website like JA,WF that has idealscope and are in similar size.

But haven't see any stone myself in person and probably will not have a chance to do the following test, I want to ask if any body have the experience to tell me what i'm trading off in the simple term.

assume i'm keeping size (1.5-1.6), clarity(VS2)
Stone A is F color has a low HCA <2 score but has only normal idealscope, let's say fair light return and shallow or deep proportion.
Stone B is H color has a low HCA <2 score but has excellent light return and ideal proportion.

What will I observe here if i just look it through my plain eye.

What I read now is
Stone A will look much shinier and sparkly (from light return) if you look the regular distance, eye to hand.
Stone B will look whiter(noticable since it's F vs H) if you compare them side to side.
and what does shallow and deep means?

Seems from all the post here, it's a good move i should make to go from F to H, right?