ideal depth?

[Tuffy]

may I know what's the ideal depth to determine if a stone is too shallow such as to result in a window or lack of lustre?

Is there a formula that you folks use to work this out when you examine a stone online?

thanks much for your help!

 

[Lady_Disdain]

It would depend on the material (different RI need different angles) and the cut (fancy cuts have different depth percentages). The best way to judge is by carefully analyzing the picture and training your eye to spot a window.

 

[chrono]

Lady D is correct; there are too many variables to have an ideal depth. Sometimes a stone as low as 60% depth or as high as 90% depth look great. The disadvantages might be that the shallowish stone might show a tilt window at the slightest angle and the overly deep stone faces up very small for the carat weight, essentially paying more for what cannot be seen. In general though, anything between 65% to 75% is quite safe. Divide the total depth by the average length, multiplied by 100 to get the depth percentage. Understanding what you see in pictures and in person will be more reliable.

 

[Tuffy]

thanks for the info! appreciate it!

 

[distracts]

I just kind of wing it based on what I've seen work and not work on other stones, if I can't tell from the picture. Usually I can tell from the picture. Also, if there's not a head on picture, I suspect a window. If there is neither a head on picture OR a profile shot (which, well, you can tell just by looking if a stone is too shallow), only weird angled shots, I move on.