Trying to narrow down diamond selection (with chart!)

[RoachForLife]

Hey all,
So Im getting close to picking everything out and still havent quite figured out how to best read the ASET / IdealScope images. I know more red is good but beyond that Im still a little lost. Anyhow I do have some minimums so I went ahead and filtered these already based on my personal minimums (below). I then (like the dork I am) put this all into a spreadsheet for easier comparison. I then looked the Knowledge Base here on PS and what the 'Ideal' standards are (also below) and color coded my chart accordingly. So anything in red is outside of the 'ideal standard' and anything in blue is close to the edge of the range. So in this case, the items that arent colored would be best (my assumption).

So at this point I have 15 on my list and trying to narrow things down.

Additionally I am still finalizing the setting so I included some pictures in the spreadsheet (see the Pictures tabs). If you see anything youd suggest from the 3 vendors Im looking at or any other suggestions please let me know.

Thanks guys!

SPREADSHEET LINK = ​https://docs.google.com/spreadsheets/d/1Kj_18udmeGzeYro-z_FKwm5W7uK9aT1kc9A_zBhObI0/edit?usp=sharing


My personal minimums
Cut = Princess Cut
Cut = Excellent / AGS1 or better
Clarity = VS1-SI1
Color = H or better (G-H likely)
Caret = 1.2 - 1.4ct
Budget for main diamond = $7700
Would likely pay for via bank price to save money (unless you guys feel thats a bad idea)
Vendors = GOG, WF, James Allen. Open to others if you guys have suggestions



Princess 'Ideal Standards' according to PS knowledge base
Depth = 64%-75%
Table = 62-68%
Girdle = Very Thin to Slightly Thick -OR- Thin to Thick
Crown = 10-15%
LW Ratio = 0.95-1.05

 

[Todd Gray]

This is adapted from an explanation I wrote awhile back, it should help you understand the different colors of an ASET:

The ASET uses the colors red, green, and blue to represent different intensities of brightness and contrast, it uses the tones black and white to indicate light leakage. Each color is used to represent a different range or angle of light as is available from that range of the earth’s hemisphere. Specifically, the color red is used to represent light which strikes the diamond from perpendicular to the table facet, up to forty five degrees. This is the brightest range of light available to the diamond and these sections of the diamond will be more brilliant.

The term brilliant as used in this connotation, refers to the brightness of the diamond and not white sparkle, which is also referred to as brilliance. The color green represents light which is not quite as bright, it strikes the diamond from 45° out to the edge of the horizon. While the areas colored green represent areas that are less bright, they are still bright, and the slight difference between the areas which are red and green, serve to increase the contrast within the diamond.

Contrast is represented by the color blue, it is the difference in shades of tone and color which enable our eyes to see depth, it is a critical factor of visual performance within a diamond, and creates a phenomena known as static contrast which creates the illusion that a diamond is sparkling when it is being viewed in a lighting environment where UV light is minimal, such as an office illuminated by fluorescent lighting.

It is completely normal for the center region of the table facet to be red or green in color, and quite often it is a combination of both colors, because they share the edge of the 45° spectrum, which separates the two colors. If you look at the construction of an ASET scope, you will see that the two sections of red and green are connected, therefore any light which enters the diamond along the seam may appear either red, green, or a combination thereof. The color blue represents contrast which is what enables our eyes to see, this is light which could have entered the diamond, but which is being blocked by our heads (or a camera lens) as we observe the diamond.

Look for a reasonable amount of consistency in the distribution of red, green, and blue throughout the diamond as it usually indicates a higher degree of optical symmetry, which when combined with tighter proportions and specific facet structures, will result in a higher volume of light return and better sparkle factor. Note that my personal preference is for princess cut diamonds which feature 2-3 chevron facets on the pavilion section, lots of threads on this to be found by searching PS.

 

[RoachForLife]

Thanks for all the info. Regarding the chevrons, are you saying 2-3 is preferred or that perhaps a higher count is even better? Say like 4, for example

Thanks

 

[RoachForLife]

bumpity. appreciate any help you guys can offer. Thanks!

 

[RoachForLife]

Updated my chart to include the AGA cut class tool rating. Thanks all!

 

[RoachForLife]

Gypsy, please help!

 

[Gypsy]

I'm sorry. the AGA cut tools are unnecessarily restrictive. Most AGS0 princesses have 70% tables. And that's fine. Crown height isn't listed on lab reports. So unless you get a Sarin you aren't getting that. Avoid very thin girdles and very thick ones (unless the spread is still good).

Just remove those entirely. Stats don't predict performance with princesses. Learn to read an ASET and stick to AGS0.

I would expand to HPD and BGD as vendors as well.

I can also 'read' stones on JA for you, if you want some GIA options, and then you can request an ASET.


And finally, read this: http://www.briangavindiamonds.com/engagement-rings/pave-and-side-stones/kirstys-halo-platinum-5765p#more

 

[Gypsy]

Then you need pictures and an ASET.

The numbers are meaningless. That lab report tells you NOTHING about how the diamond will perform.


Here is what I mean. Compare these two:

http://www.jamesallen.com/loose-diamonds/princess-cut/1.00-carat-g-color-vs2-clarity-sku-295886
G color
VS2
Depth 76.3
Table 69
Ratio: 1.01
Excellent polish
Good Symmetry
Girdle Medium

http://www.jamesallen.com/loose-diamonds/princess-cut/1.00-carat-g-color-vs2-clarity-sku-283672
G color
VS2 clarity
Depth 76.2
Table 69.9
Ratio: 1.02
Very good polish
Very good symmetry
Girdle Thin to Slightly thick

Numbers are VERY close right? And the first one has a better girdle. And while the symmetry on the first one is only good, that's not a disqualifier with princesses.

Look at the prices. The first stone is more expensive than the second. So... you'd think the first one would be better right?

Now look at the pictures. The first one is a VERY dark stone, and frankly a dog as far as princesses go. Second one is an AGS0 with ideal light return and is very bright, with just enough patterning to provide contrast.

In summary. YOU NEED AN ASET AND IMAGES.

Also, you don't need idealscopes for princesses as they don't help you.

 

[RoachForLife]

Thanks for the response, def appreciate it!

A few questions based on your response...
Girdle
When you say the spread is good, how many 'steps' would be considered good? Looking at the AGA tool there are 9 options from Extremely Thin to Extremely Thick. Would a 'good' spread be something over 4 spots for example? So thin - Med for instance would only be 3 steps total and probably not very good, but something like Thin - Slightly Thick would be 4 spots total and would be acceptable? (also GOG doesnt list the worded girdle info but has some mm values. Im guessing there is a conversion table somewhere for this)

ASET
I'm still working on understanding the ASET images. Red is good, green is next best, and blue is necessary for contract. White and black is generally bad. So at a basic level, more red/green and less white/black is what I'm looking for.


I will go through the other sites today for sure and update everything accordingly.
Thank you again!