16 replies to this topic

[esaod]

I have found a diamond that I think is a good deal with a good cut. I have heard that the cut alone is not good enough anymore. A gemex evaluation of the diamond is more important. I would appreciate an evaluation of this diamond and the price and weather a gemex review is necessary.

Round stone
GIA
1.58 carat
clarity VS1
color H
7.42-7.46x4.65mm
Depth 62.5
table 57.1%
girdle medium to sl thick faceted
polish VG
symmetry Ex
fluor None
crown angle 35 deg.
pav angle 41.2 deg.
culet None
for $11,250

[James Allen]

esaod,

You have found a great diamond and a really great price. If this is an "in-store" deal then your jeweler is very aggressive in pricing and is providing you a price quote comparable with the best online shops. If this is from an online dealer you can feel confident that you're getting a very fair price as well.

As to the cut/gemex issue, I don't think throwing out the diamond and limiting yourself to only diamonds with BS reports is necessary. There are other tools (such as lightscope images, HCA scores, personal vendor feedback) that can help steer you towards a beautiful diamond that you will love.

With that said, the diamond you selected has a pavillion angle of 41.2 degrees. This angle is on the "steep" side of the Ideal range. A 41.2 pavillion combined with a 35.0 crown is not the combination of angles that will typically produce the the highest BS scores. Does that mean the diamond isn't beautiful? No, not at all. This diamond is better cut than 99% of the stones you find in chain stores. The question becomes how much more do you want to pay for that last .5%...

[barry]

Diamond analysis and evaluation have come of age and a Gemex Brilliancescope is IMO an essential tool especially if you are shopping on-line and do not have the ability to "see" the diamond in person. It makes no sense to spend thousands of dollars with one hand tied behind your back and shut yourself off from the amount and depth of analyses that is currently available. It is amazing that some consumers still shop for diamonds this way but would never consider buying a car or home with this type of limited and/or partial information.

Of all the diamond tools currently on the market, the Bscope is IMO (having worked with it for the past five years), the best. It depicts to you the intensity, distribution, and interaction of white light, colored light, and scintillation as well as showing you the level and amount of contrast in the diamond.

To show you a real-life graphic example of what I'm talking about, I've attached an analysis of an EX-EX "Ideal Cut" that has BETTER NUMBERS than the diamond you're asking about, which we evaluated for a colleague of ours. Light performance as measured by the Brilliancescope is mediocre and not commensurate with the expectation for such a "Numbers" diamond.

Was it a "nice" diamond? Yes. Was it better than the diamonds being offered in 'Maul' stores? Of course, but this is not a valid comparison as again you're comparing apples to oranges.

For the money you're spending and the level of your expectations, you owe it to yourself to get as much information as possible. Get back to your vendor and see if he can supply you with this information.

Good Luck.

Attached Images

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[barry]

easod;

How you doing?

[esaod]

Hi again,

I'm still considering the above mentioned stone.

My concerns are that the pavilion angle is 41.2 which although is in the AGS 0 range. it is probably too steep. I've read that it should be 40.75 to be "ideal". Also that fact that the total depth is 62.5% also seems high. Although I don't directly have a crown height, if the pavilion depth is 43.5% and the girdle is 1.2-1.7%it seems that the crown height would be 17.3-17.8% (correct?). Isn't that too high?
When I ran the numbers on the Holloway cut advisor (Online), I got:

Factor Grade
Light Return Very Good
Fire Good
Scintillation Good
Spread or diameter for weight Very Good
Total Visual Performance 3.7 - Very Good - Worth buying if the price is right .

This doesn't seem that great for a supposed AGS 0.

What do you think???

[jan]

What kind of light return analysis are you doing on it? It sounds like the blind method where you put in a couple of numbers and spit out a prediction. Without actually visually examining the stone unfortunately that method should be banned since it is highly inaccurate. I sure wouldn't base a buying decision on it.

[ben]

Quote

Without actually visually examining the stone unfortunately that method should be banned since it is highly inaccurate.

This is strictly a matter of personal opinion. It is not necessarily "highly inaccurate".

Also, "banned" is a bit strong, IMHO. Don't scare the poor guy!!

Many people do purchase stones strictly "by the numbers" with good results. Some people like Chevys, others like Fords. Neither is right or wrong.

[barry]

Ben;

Nothing "alarmist" or "personal opinion" about Jan's post. It's based on years of experience in evaluating diamonds.

She's right.

[esaod]

...

[esaod]

Still between 2 diamonds


Round stone #1
GIA
1.58 carat
clarity VS1
color H
7.42-7.46x4.65mm
Depth 62.5
table 57.1%
girdle medium to sl thick faceted
polish VG
symmetry Ex
fluor None
crown angle 35 deg.
pav angle 41.2 deg.
culet None
for $11,250



Round #2
GIA
1.5
clarity VS2
color H
7.36-7.44X4.45
Depth 60.2%
Table 57.1%
girdle medium to sl thick faceted
polish VG
Symmetry GOOD
fluor None fluor None
crown angle 34.9 deg.
pav angle 40.2%
culet none
for $10,400

Stone #1 has a steep pav angle and a deep total depth. Stone #2 has a better total depth but a shallow pav angle, but most importantly only a GOOD symmetry. Should I go with better symmetry (more money) or a better total depth. Using the Holloway cut advisor I saw online, Stone #2 looked better, but how accurate can that be??
Some guidance would be appreciated. Although each factor is important, which are the most important. Is GOOD symmetry less or more important that the proportions? Although I am told both are AGS 0, neither seems to be "ideal".
Thanks

[ben]

barry, on Wednesday, Nov 30 2005, 06:46 PM, said:

Ben;

Nothing "alarmist" or "personal opinion" about Jan's post. It's based on years of experience in evaluating diamonds.

She's right.

I respectfully disagree.

There's nothing wrong with buying a diamond "sight unseen". Sure, looking at it is good. But I'm just not buying that it's as critical as Jan would suggest. If all the numbers check out but the stone turns out to be a dog when you receive it, you just return it.

[ben]

esaod,

I think you have found two very good diamonds, and regardless of which one you select, you will do well. You have obviously done your homework and are now at the point of "diminishing returns" for the effort expended. Congratulations!

[barry]

Ben;

That's all well and good if the consumer is "seeing" both stones, side by side. From the above poster's question it appears that a decision is being made sight unseen on making a purchase between two choices based solely on an advisor "score" that gives partial, averaged information by measuring only 17 of the 58 facets that comprise this shape.

If you're comfortable recommending a purchase of thousands of dollars on this type of
information, OK.

[ben]

If he doesn't like what he sees when it arrives in the mail, he can return it (assuming he bought from a reputable place with a decent return policy).

[esaod]

I have seen both stones, they are from 2 different local stores. I really have no idea if they are showing brillinace and fire that is expected for this price since I am not a professional, plus the lighting in the store can be deceiving. Based on the above, would you recommend the deeper one with Excellent symmetry or the more shallow one with the good symmetry.
Just some general guidance would be appreciated. Unfortunately, I can not see them side by side.

Also, do the above really represent "ideal" like the store claims?

[denverappraiser]

Esaod,

They both look like they have pretty good potential but neither one meets the classic definition of AGS-0 because of the slightly large table and the G symmetry. The current definition requires an AGS grading report so it doesn’t really meet the new one either although they still require VG or better on both polish and symmetry.

I disagree that the HCA is useless but I think you’re reading far more into it than is appropriate. It is a distilling of some of the stones data into a single score that can be useful at times but it’s only as good as the original data. Where did you get the crown and pavilion angles? They aren’t on the GIA report. Assuming that they were supplied by the dealer, they probably came from a Sarin or Megascope scan. These scans average the 8 crown main and 8 pavilion main angles into two numbers like you’re seeing (the 17th facet that Barry mentioned is the table). This averaging process can lead to trouble and a considerable variation here. It’s one of the possible reasons for the ding on the symmetry grade . A Sarin reported angle of 41.2 deg, may, in fact, not have a single facet of that measurement! It’s also worth noting that Sarin reports a margin of 0.2% on their equipment. This is pretty good, but if you’re concerned about that 3rd decimal place it can be important. The HCA/Sarin is good for sorting out the bad stones but it doesn’t contribute much towards separating the very good from the excellent.

As you’ve discovered, the lighting environment is terribly important and it makes things difficult to compare between 2 different stores. This is a much more important variable than any of the above issues. Step away from the spotlights over the jewelry counter and you may find it easier to compare. In the end, you can make get them both appraised and you’ll have the opportunity to view them in the appraisers lights.

Most of the reason stone #1 costs so much more is the VS1 clarity and the fact that it’s slightly larger.

Neil Beaty
GG(GIA) ISA NAJA

[barry]

denverappraiser, on Thursday, Dec 1 2005, 04:28 PM, said:

I disagree that the HCA is useless but I think you’re reading far more into it than is appropriate.  It is a distilling of some of the stones data into a single score that can be useful at times but it’s only as good as the original data.  good for sorting out the bad stones but it doesn’t contribute much towards separating the very good from the excellent.

Neil Beaty
GG(GIA) ISA NAJA

There has recently been a considerable revision and re-writing of the guidelines by it's inventor under which this advisor tool should be used.

It is to be used as a "reject" tool which may flag poorly cut and proportioned stones and not as a "pick" tool that is sensitive enough to differentiate between two candidates as has been offered up for public consideration in this posting.

As such, it is useless as a basis to make this kind of decision.

As Neil suggests, do your best to view them in person in a variety of lighting conditions.