Deeper cut diamond?

[Carnell]

What does somebody mean when they say one diamond is deeper than the other so it looks smaller? Do they mean the difference in the depth and table percentages? The bigger the difference the deeper the cut is?

 

[valeria101]

No... not quite.

Deep cut stones have smaller diameters in absolute terms than shallow cut ones of the same weight (and hence volume).

This has nothing to do with the table size.

The table and depth % on the lab reports are taken relative to the shortest diameter of the stone ... So large depth % means that the stone has a relatively small diameter for its weight.


Now, that the easy part. The opposite (less depth => larger diameter and larger looking diamind for the weight) is not always true because more factors come into lay (minor facets for fancy cut diamonds, and girdle width for both rounds and fancies).


Hope some of this makes sense. Explaining things is not my talent

 

[Lord Summerisle]

almost there...

leave out the Table info.

at minimum a GIA report gives the actual actual dimension on a diamond... take a 1ct diamond for example... diameter would be measured around the 6.50mm mark, and depth... umm.... 3.9mm mark

now in terms of depth... i think ideally we''re talking 60% depth... i.e. to find depth percentage divide the depth measurement by the diameter... so 3.9/6.5 = 0.6 x 100 = 60% (dont worry, the depth % is normally given on a diamond cert no matter who the cert has been issued by)

now

take a deeper diamond... say 63% depth

6.5mm x .63 = 4.1mm which would mean the diamond weighed more for the same visual size... its diameter.

take these 2 examples.

http://www.whiteflash.com/hearts_arrows/A-Cut-Above-H-A-cut-diamond-1177149.htm - a 1.01ct diamond, has a depth of 60.6% and measures 6.55-6.57X3.97

and this one

http://www.whiteflash.com/hearts_arrows/A-Cut-Above-H-A-cut-diamond-1177148.htm - a 1.04ct diamond, has a depth of 61.1% and measures 6.56-6.59X4.02 (i.e. 0.5% increase in depth, 0.03ct heavier, $775 more and is identical in diameter)

does that help?

the situation would be more pronounced if we were comparing a diamond with 60% depth to a stone that had nearer 63% depth