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Which 1 Carat Diamond Shall I Choose

C

cyang

Rough_Rock
Joined
Sep 22, 2010
Messages
37
Hi,

I saw this ring from costco. There are these 4 that i can choose from. They all priced as 4,999.

The report are from IGI. And they are IGI appraisal report. Only diamond 2 happen to have additional GIA certificate. That is why i can get additional parvillion angle and crown angle information.


1. diamond 1--
Measurement: 6.38-6.42-3.97 mm; weight: 1.00carat; depth: 62.1%; table: 56%; Corlor: H; clarity: VS1; Polish/Symmetry: Excellent/Excellent; Fluorescence: None; Girdle: Medium; Culet: None; appraisal value: $13,875

2. diamond 2--
Measurement: 6.54-6.60-3.88 mm; weight: 1.01carat; depth: 59.0%; table: 61.0%; Corlor: l; clarity: VS2; Polish/Symmetry: Excellent/Very Good; Fluorescence: None; Girdle: thin to Medium; Culet: None; crown angle: 33.0 pavilion angle: 40.8; appraisal value: $11,755

3. diamond 3--
Measurement: 6.41-6.45-4.02 mm; weight: 1.02carat; depth: 62.6%; table: 55%; Corlor: I; clarity: VS1; Polish/Symmetry: Excellent/Excellent; Fluorescence: None; Girdle: Medium; Culet: None; appraisal value: $12,565

4. diamond 4 --
I can see a small black spot from table face up. I wonder how can black spot one from the most obvious position be rated as VS2?
Measurement: 6.57-6.63-3.93 mm; weight: 1.04carat; depth: 59.5%; table: 60%; Corlor: I; clarity: VS2; Polish/Symmetry: Excellent/Excellent; Fluorescence: None; Girdle: Medium; Culet: None; appraisal value: $12,105



From appearance, I like diamond 4 the best, because it appear the biggest. But as i said, although the carbon spot (color: black) is not big enough for naked eye to catch. But under the loupe it is quite obvious and it is right at visible at the table (in the middle beteen the center and the diamond edge).


From price, most people will choose diamond 1, i guess. But Is those appraisal value really trustable? I heard IGI's appraisal value tend to be on the high side.

I know most people will choose diamond 1. But it is smaller than the average measurement (6.45 to 6.5). That is the most i am concerned. Diamond 2 is slightly bigger. But the measurement (table, depth) are not that good either, is it?

I almost rule out the diamond 2, since symmetry is only very good, not excellent. And that one seem to be shallow cut, given the depth is shortest.

Based on the existing data, table, depth, and measurement, are you able to sort out the cut sequence? There is 4C to follow. It is the cut to be the hardest one to understand.


Which one will you recommend, in terms of overall value, quality, look and sparking extent? I know some diamond have bigger girdle circumstence, but the proportion is bad and the light does not reflect, and it might look darker in that case.

I really appreciate if I can hear your professional opinion on this.

Thanks! --- CY
 
The appraisal value for all 4 rings are too high. $4,999 is good for the value of the diamond. But I don't know how the appraiser tack on another $6000 to $7000 on to value. H and I diamonds in 1.0-1.04 ct essentially looks the same. If you like diamond 4 after visual inspection, then that should be the frontrunner.
 
We need the crown and pavilion angles to tell how well the stones are cut. We only have them for the GIA stone.

The second stone scores a 1.7 on the HCA.
Factor Grade
Light Return Very Good
Fire Excellent
Scintillation Very Good
Spread
or diameter for weight Excellent

Total Visual Performance 1.7 - Excellent
within TIC range

Cant help you with the rest. You cant just go with the stone with the biggest diameter...if its too big for its weight
it could be a shallow stone. If you let us know your budget we can look around and see what we can find. What
are the real prices on the stones? Appraisals dont really mean much when buying a stone.
 
It is good to know HCA.

Diamond 2 has big enough diameter. Does the HCA tell it is not a shallow cut?

What about symmetry? The symmetry is only very good, instead of excellent. Is that something i shall be concerned?

Thanks.
 
The cut adviser.

https://www.pricescope.com/tools/hca

It is a shallow cut, but the angles are complimentary to each other for optimal light return.

Difference between a VG and Ex grade in polish and symm is not discernible to the layperson without training and tools.
 
I am confused. Shallow cut is supposed to be bad, right?

Diamond 1 is the best on color and clarity. Is that a common choice? Is it too small vs other 1 carat commond diameter? By looking at limited data over there, can that be too deep cut?

Thanks.
 
Sorry, I should not have said it is shallow. It is slightly on the shallow side of tolkowsky ideal cut (TIC) dimensions, which is a more balance proportion. Not shallow enough to be a problem, which is fish eye or obstruction. Some prefer the large table, some do not.

For the others, really no way to guess as from the depth and table, there can be many combination of crown and pavilion angles, some good some bad.

I would not select a stone based on color/clarity grade but on which appeals to me. Have you check all the stones side by side in different lighting conditions?
 
I would prefer a stone with a GIA cert so would narrow it to that. I would eliminate diamonds with eye visible inclusions. Which diamonds does that leave (eye clean GIA certs)? What are the cut grades on the GIA stones?
 
The diamond ring is from costco. They only have one light setting, some store even have the desk lamp kind of lighting, not the white one. I always feel rushed (even they didn't say so) when their staff show me diamond. And four rings are from four stores in the area. I wish i can put them together and compare. Besides, my eyes are not smart enough to know which one sparks more.

Which one appears more to me? Diamond 4 has black spot, once i catch it by loupe, i always remember it. Diamond 2( 6.54-6.60-3.88 mm), the symmetry is not excellent, but i really like it being big diameter. Diamond 1(6.38-6.42-3.97 mm), too small, right? Diamond 3(6.41-6.45-4.02 mm) is only a little bigger than 1, and with deeper pavillion.

I decide to pick one out of those four, because i really like the setting. It is tiffany set with knife edge. if you have to pick, which one will you pick?


Thanks.
 
is both (6.38-6.42-3.97 mm) and (6.41-6.45-4.02 mm) too small for 1 carat average diameter?
 
cyang said:
is both (6.38-6.42-3.97 mm) and (6.41-6.45-4.02 mm) too small for 1 carat average diameter?
Click to expand...
this stone is 62.6% maybe a little too deep?
 
Nope, the diameter is not too small, considering the table size, could have a high crown.

#4, ya, that is a problem for certain eye-clean stone.

Not sure how Costco works but can you ask a store if they could consolidate all 4 stones together?
 
Costco is a warehouse. They don't have very good way of selling diamond. People buy their jewerly based on trust on the brand name and return policy.

One more question, i remember for some diamonds, when viewing from side (not from facing to the table), why do i see a ring in the mid pavillion depth or towards cutlet? It is not fish eye, fish eye is the ring when you view facing to the table. So what is the ring from the side view?

Thanks.
 
That is the girdle reflection. All stones should have it.

EDT:
Something like this?
golfer1.jpg
 
With regards to buying a well cut stone, how about buying an idealscope and learn how to use it the go shop again?

It is not that expensive for a basic scope.

http://www.ideal-scope.com/cart_order.asp
 
Yes, the mid-ring is like what you show in the picture. Initially i thought diamond has a big inclusion. What is that?

For the idealscope, i will definitely look into that. I will check with you again if any question. I do have a loupe, where i got it from amazon. It was less than 5 bucks. It says 30x. But i am not sure if it is really 30x. Is idealscope different than loupe?

Thanks.
 
The image shows the 'girdle reflection', basically the girdle facets of the stone is being reflected.

Idealscope shows the light return of a stone, basically how well a stone performs, is quite useful for round but not as useful if you are going to look at fancy shape cuts, then an ASET will be better suited.
 
Thanks for the reply again.

--- "The image shows the 'girdle reflection', basically the girdle facets of the stone is being reflected."

Does it mean it is a bad cut? or it is totally normal?
 
cyang said:
--- "The image shows the 'girdle reflection', basically the girdle facets of the stone is being reflected."

Does it mean it is a bad cut? or it is totally normal?
Click to expand...

Perfectly normal.
 
Can I ask why it has to be costco? Their prices may be better than an overpriced brick and motor but it no better than an online vendor who will stand behind the workmanship, allow your choice of settings, and be there should you want to upgrade. Just my opinion, but I would never find a stone with just an IGI cert to be an acceptable engagement ring stone.

To each their own but I think you might consider a diamond from a reputable company specializing in jewelry. Here's an example fitting your price:

http://www.jamesallen.com/diamonds/I-VS1-Ideal-Cut-Round-Diamond-1238208.asp

or

http://www.jamesallen.com/diamonds/I-VS2-Ideal-Cut-Round-Diamond-1316322.asp

These would be available from almost any vendor, but it's nice to see the pictures on James Allen.
 
Stone-cold11, for ideal scope, i did check it out.

Are you suggesting the beginner one at $25? I have a loupe at 30x, although i never know if it is really 30x or not even 10x. I got it from amazon, cheaper than 5 bucks. How is ideal scope at 6x magnification better than loupe at 30x?

And can beginner ideal scope help to identify if a diamond sparks?

Thanks.
 
cyang said:
Stone-cold11, for ideal scope, i did check it out.

Are you suggesting the beginner one at $25? I have a loupe at 30x, although i never know if it is really 30x or not even 10x. I got it from amazon, cheaper than 5 bucks. How is ideal scope at 6x magnification better than loupe at 30x?

And can beginner ideal scope help to identify if a diamond sparks?

Thanks.
Click to expand...

Idealscope looks at the light return, not the same purpose as a loupe.

Yap, beginner idealscope is good enough. Just make sure you know how to use it and interpret the image.
 
Just some update, Sorry i was not patient enough to get a idealscope to help me through. I guess i am not confident about my untrained eyes.

We ended up purchasing diamond 2. I First, it came with GIA. Second, GIA says it is excellent cut; and HCA calculator return score at 1.7. I don't have professional eye. I will just trust those numbers. Other diamonds do not come with GIA. I have no base for their cut information. I am happy that diamond 2 appear to be big.

Thank you all for helping me.
 
Good luck. :)
 
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