GIA certificate Excellent Vs HCA rating good?

[jana1120]

Helping my 25 year old son diamond shop - have short timeline due to situation that is creating a surprise proposal. I have read almost everything on this site and asked some questions and gotten lots of helpful info here. We went to a local jeweler today just so we could look at settings and diamond sizes in person and really liked the settings they had more than any we have seen at any of the online sites. We told them what we were looking for in a diamond. I had my table of ranges for depth, table, crown & pavillion that I had gotten from experts here. Here is what they showed my son. A GIA certified diamond. The certificate said SI1, F, excellent cut, depth 62.2, table 59, crown 35, pavilion 41.2 and they told me it was triple ex. When I put the parameters into the HCA tool the rating only comes is only good at a 4.1. The price for a 14 carat white gold pave setting with .25 in diamonds and that stone was $7k. How can the GIA certificate rate it an excellent cut when it comes out as only good on the HCA? I'm confused and feel like this diamond may be a bad buy. And I think he should go down to a lower color and up on the clarity. Thoughts anyone?

Here is a diamond I found on whiteflash that came out 1.8 excellent on the HCA scale. Thoughts on this one?

http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3403889.htm

 

[ecf8503]

GIA's "excellent" range is very broad - there are some super performers in there as well as some that may have just made the cut. This sounds like one of them - it has a big table and is a bit steep/deep. Keep looking.

 

[jana1120]

ECF8503. What do you think of the link I posted to Whiteflash? That one came out as a 1.8 excellent on the HCA scale?

Thanks!

 

[ccuheartnurse]

The one you linked to is a lovely stone. Crown angle is a bit deep but otherwise, it can be a great stone. Here is an H, which is AGS certed & the numbers fall in line with what is considered better than the G, in relation to the crown angle anyway. I do realize it's 1 colour grade lower than the G. It might be worth a shot looking at because there really isn't that much of a difference between a G & an H.
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3520058.htm

I didn't have a chance to compare plots but maybe 1 is better than the other or cleaner than the other. Good choice going with WF as he can upgrade it later if he chooses. A gorgeous stone now & a gorgeous stone later on. Win - win.

All the best to your son & to you, mother in law.

 

[autumngems]

This confusez me as well as I have found some stones listed as triple ex but rate poorly un on HCA.

 

[MissGotRocks]

GIA XXX cover a broader range than AGS0 stones. The HCA can help you weed out the ones that you might not want to consider if excellent cut is what you are looking for. You can always post stones here for some advice before purchase!