Analysis of 2 ECs with ASETs, videos and loads of photos

[diamondhoarder]

I have been searching for my perfect EC for a a couple of years. The advice I have received from the step cut enthusiasts on this site has been amazing, and I have now found "the one". Having looked at many ECs in shops and online, I finally narrowed my search to two loose diamonds and had them sent to me so I can compare them side by side. The results have been surprising in some respects and I wanted to share the info here in case it can be of help to others searching for a great Emerald Cut.

First off its worth mentioning that I was looking for something with a smaller length to width ratio than is the norm for ECs - anything between 1.1 and 1.2. I was also looking for eye clean, and with a white face-up. But on top of that I was determined to find a stone with lovely fire, a great facet pattern and a decent face-up size for the weight.

The two finalists were:

J, VS1, 1.14cts, med blue fluorescence, ratio 1.18
F, SI1, 1.03cts, no fluorescence, ratio 1.11

Vendor Photos

The J:



The F:



From the photos alone I would pick the F every time. It seems to be the brighter stone, with the brightness evenly spread through the stone, and a lovely fact pattern with noticeable steps. The J appears much more tinted and because of the angle the photo was taken from it was difficult to judge the true "face up look". So I felt it looked far less lively than the F.

However, the specs for the J were more favourable on paper than for the F, so I felt it was worth seeing in person.

J, VS1, 1.14cts
Polish Excellent
Symmetry Excellent
Fluorescence Medium
Table % 62%
Depth % 65.9%
Culet None
Girdle Thin to Medium
LxW Ratio 1.18
Measurements 6.52mm x 5.51mm x 3.63mm

F, SI1, 1.03cts
Polish Very Good
Symmetry Excellent
Fluorescence None
Table % 67%
Depth % 65.1%
Culet None
Girdle Thin to Medium
LxW Ratio 1.11
Measurements 6.20mm x 5.58mm x 3.63mm

ASETs

These were not available from the vendor so I used my own ASETscope with a white back light.

Here is the ASET for the J:



And for the F:



Both ASETs seemed quite promising, although the J seemed to have more red, more evenly distributed across the stone. That was a surprise, given the uninspiring photo. The contrast pattern (in blue) in the F stone looked quite striking to me and there was still a good amount of red and green. Neither stones seemed to show too much white (in my opinion) which I understand to be light leakage. More pics coming

 

[diamondhoarder]

Light performance

Here they are in person, the J on top, the F below:



The F seems to have more darker areas in the diamond whereas the J has a brighter appearance right across the diamond. When photographing them it was clear that the J has much more fire. In fact it was quite hard to get a photo of the J where it wasnt throwing back some color of the rainbow from at least one of the long facets.



This second photo captures the darkness issue with the F even better



This final photo shows the F in a favourable light where you can see how the contrast pattern shows the lovely even step patterning in the stone. But even in this photo the J is busy throwing some blue and turquoise fire out of 2 facets.

I think its interesting to compare the ASETs pics to the side by side photos of the two diamonds. You can really see how the blue areas of the ASET on the F stone highlight the steps, but also how the increased amount of red and very small amount of blue in the ASET on the J stone seem to, in this case, make for a brighter stone overall.

Crown angle

A lot has been written on PS about the effects of crown angle on the fire and scintillation of diamonds, and there is a whole thread about how it effects ECs. I dont have the crown angles for these two diamonds, but here are the side by side profile shots. The F is on the left, the J on the right.



In the case of these two diamonds, the expectation that a steeper crown and smaller table will produce more fire and faster scintillation seems to hold up.

 

[Sphene]

wow J every time for me

 

[gregchang35]

J for the win!
THANK You for posting your assessments on the 2 choices...

It will help others in the same boat...

lovely pictures...to help with your decision processes.

well done!

 

[diamondhoarder]

Clarity

The general advice with ECs seems to be to try and go for VS1 or higher if possible in order to ensure that the diamond is eye clean. The J stone is VS1 and is eye clean, as expected. The F stone is SI1 and is also eye clean. The inclusions in the F stone are nicely hidden in the facet pattern and there is nothing to see through the table. Even with a 10x loupe the diamond is remarkably clean. In spite of the clouds, the stone is not hazy as all. So it is possible to get an eye clean SI1 in an EC!



Color

This for me was one of the most interesting observations. When my husband first saw the J stone after seeing the F stone, he immediately said that the J faces up whiter. This was in indoor lighting so should not have been as a result of the medium blue fluorescence. I myself felt that it certainly seemed brighter and the better looking of the two stones. I can see some difference between them in some lights and in some angles, but there is not as much difference as I would have expected. I think this primarily comes from the fact the the J is throwing back more brilliance and fire, so the color is masked more, whereas the F suffers from dark areas in the stone which appear to pick up and reflect dark colors from the surroundings. This has the effect of making the F seem tinted in some lights.

This pic illustrates this perfectly (J on the right)



Whereas this one shows the body color of the J (on the right again) from the side view. And you can also see the J's steeper crown on this one again.



Effects of fluorescence

In natural daylight the medium blue fluorescence certainly helps the J stone even more, making it face up much whiter than expected. This diamond doesnt show any negative effects from the fluorescence. There's no haziness/ milkiness in any lighting conditions



So my final conclusion is that the J is the hands-down winner. and the F stone will be making its way back to the vendor after christmas.

 

[diamondhoarder]

wow J every time for me

J without a doubt!

You beat me to it! I was still finishing adding to the post (can only seem to post 4 pics at any one time). I also havent been able to upload videos despite referring to that in my title.

 

[gregchang35]

wow J every time for me

J without a doubt!

You beat me to it! I was still finishing adding to the post (can only seem to post 4 pics at any one time). I also havent been able to upload videos despite referring to that in my title.

Yes, after i posted, i saw you posting more, so i had edited what i said as it was too late to delete it....

Congrats on making the decision....now for the setting!

 

[woofmama]

I've been waiting to see what your choice would be. It's great that you've done such a detailed thread for all the EC lovers, especially those looking for a square stone. That J would have been my choice as well, hands down, it's the clear winner!

Interesting observations on J looking whiter & brighter, while I'm sure the MBF plays a part in that effect I believe the cut has a bigger influence. Seeing the steps throw multi colors is the thing I enjoy the most about my EC. The crown height on that J looks excellent as well.

Love it & I look forward to seeing how you set it

 

[RetroTreeGal]

Thank you for taking the time to post this- it was very educational and fun!