Often, GIA triple excellent diamonds may not fall under strict proportional criteria for Table, angles, etc, and I’ve really enjoyed using diamondscreener to compare proportions. As has been mentioned, many GIA triple excellent diamonds might fall at an intersection with the ideal AGS / GIA excellent tool areas. 

Some diamonds might fall in the ideal areas on the tool, but have proportions outside of the very strict criteria proposed by many sources (such as Beyond4cs) 

Table: 54 – 57

Depth: 61 – 62.5

Crown Angle: 34-35

Pavilion Angle: 40.6 – 40.1

I’d like to illustrate some examples and solicit opinions! Here are the diamonds of interest:

 Diamond #1 Diamond #2Diamond #3Diamond #4Price$11,261$11,212$11,455$13,680Carat Weight111.041.01ShapeRDRDRDRDCutIdealIdealIdealIdealColorFFGFClarityVS1VS1VS1VVS1L/W Ratio1.010.9911Depth %62.361.761.862Table %55575656Crown Angle3633.534.534.5Pavillion40.641.240.840.8GIA/AGS Intersect?No (intersect)YesYesYesPolishExcellentExcellentExcellentExcellentSymmetryExcellentExcellentExcellentExcellentCuletNoneNoneNoneNoneFluorescenceNoneNoneNoneNoneInclusionsTop: small featherTop: small Crystal, needleTop: crystal, cloudTop: noneBottom: pinpointsBottom: n/a bottom: pinpoint, feather

For example – Diamond #1 – Meets Beyond4Cs’ strict criteria, but only borderline in the tool:

Next example: Diamond #2 – Does not meet Beyond4C criteria, but is in the sweet spot:

Diamonds 3 and 4 are added for comparison as they meet both Beyond4C’s criteria and hit the sweet spot, at the expense of color or price. 

As an online shopper (using a site that doesn’t offer in-person viewing of stones) – is it better for light performance to prioritize strict proportions such as those outlined by Beyond4C (Diamonds 1 – not in sweet spot, 3, 4)? Or, if hitting the AGS/GIA sweet spot in the tool (as above, Diamond #2), are more relaxed proportions acceptable?

I realize Cut > Color > Clarity, so really curious how you all would interpret the tool and evaluate these diamonds. Thanks for reading! 

Answered question

Apologies, I destroyed the formatting there..
Will add a table in subsequent post!

Image paste wasn’t working – here are the diamonds for comparison:

#1: $11250, Round, 1 Ct., F, VS1, 62.3 Depth, 55 Table, 36 Crown Angle, 40.6 Pavilion Angle , GIA 3X, No fluorescence, small feather inclusions on top – [does not fall into sweet spot]

#2: $11200, Round, 1 Ct., F, VS1, 61.7 Depth, 57 Table, 33.5 Crown Angle, 41.2 Pavillion Angle, GIA 3X, No fluorescence, crystal and needle inclusions on top – [falls into sweet spot, not Beyond 4C’s strict criteria]

#3: $11500, Round, 1.04 Ct., G, VS1, 61.8 Depth, 56 Table, 34.5 Crown Angle, 40.8 Pavillion Angle, GIA 3X, No fluorescence, crystal and cloud inclusions on top

#4: $13800, Round, 1.01 Ct., F, VVS1, 62 Depth, 56 Table, 34.5 Crown Angle, 40.8 Pavillion Angle, GIA 3X, No fluorescence, no inclusions on top, small pinpoint/feather on bottom

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