Fast and dirty way to determine HCA

[Jcm412]

I feel like I have been looking at thousands of diamonds. It is really getting really time consuming typing in all the info for HCA. Is there a fast and dirty way to determine what range a diamond will fall to atleast weed out the bad stones? Is there a particular range of measurements I should look at?

 

[kenny]

Depth under 62%
CA near 34.7 deg
PA near 40.8 deg

No clue about Table % but another poster may suggest center target value.

Keep in mind the need for the HCA.
IT's a brilliant math thing that take 4 values into account that interact.

No singe value of any of those 4 numbers is always groovy.
They interact!!!

Use the HCA.

 

[JulieN]

There is an inverse relationship, as you increase the crown angle, the pavilion angle must go down.

So you can start at some central combo, like 34.5/40.8, or 34/41. And then remember that if the crown angle is above that starting pint, then the PA should be below that starting point. But this is not a very good method, just fast, because a GIA 34.5 CA could go with GIA 40.6/40.8/41.0.

 

[diamondseeker2006]

Table: 54-58

Depth: 60-62.3

Crown angle 34-35.0

pavilion angle: 40.6-41.0

girdle: thin, med, slightly thick (or combo of those)

I always use this and it will usually keep you in the ideal cut zone.