Using GIA with HCA advice please. Doesnt make sense.

[sushi]

Hello,

Im buying a pair of studs, i have about 10 pairs im comparing, but im getting a bit lost. As they are from different dealers, im having trouble remembering what the different ones looked like... I want the sparkliest possible out of them all...

So ive taken th GIA certs and popped the data into the HCA, and im even more confused. One pair are H-VS1's Both Excellent cut, very good polish and symmetry. Then after putting the angles into the HCA they are:

3.6 - Very Good - Worth buying if the price is right
Light Return Very Good
Fire Very Good
Scintillation Good
Spread
or diameter for weight Very Good

Total Visual Performance 4.0 - Good - Only if price is your main criterion
Light Return Very Good
Fire Good
Scintillation Good
Spread
or diameter for weight Very Good

So now i am scared to buy them. I would have thought h-vs1-excellents-GIA would be good, now im not sure how much i can go buy looking at a GIA cert. How much should the HCA be referred to? As i mentioned i cant compare them all side by side, so im using as many online tools as i can to decide what is the best... please tell me what i should be doing or looking for?

Thank you

Many Thanks

 

[Amys Bling]

If you are buying without ASET or IDEALSCOPE images I would heavily reply on the HCA. If you can evaluate images I would be ok with using images to determine along with GIA grading

 

[sushi]

Hi Amy,

Thanks... Actually i am dealing with wholesalers, so they just show me the stone, and the GIA... So just because it is an excellent cut on GIA, doesnt mean it is a good stone then? And if i am downgrading on any of the HCA sections, which ones would be ok?

Finally are these worth buying?!

Thanks!

 

[slg47]

this article might help...

https://www.pricescope.com/journal/laboratory_cut_grades_what_report_doesn%E2%80%99t_show

I don't think these are necessarily 'bad', but as you can see from the article, there is variation within GIA Ex cut grade. Since you have lots of options coming to you, you can use the HCA to narrow down.

 

[Amys Bling]

this article might help...

https://www.pricescope.com/journal/laboratory_cut_grades_what_report_doesn%E2%80%99t_show

I don't think these are necessarily 'bad', but as you can see from the article, there is variation within GIA Ex cut grade. Since you have lots of options coming to you, you can use the HCA to narrow down.

yes- GIA Ex cut grade has variation and getting an excellent doesn't mean it's a perfect cut. Honestly, have you seen the stones? What do you think of them? View in all lighting. Also, how are you planning on setting the stones? If you are going for a bezel set, the light blockage will also slightly dimish the sparkle so having a stone scoring higher on the HCA combined with the bezel may not have the sparkle you are looking for.


Would I buy them? depends on other factors- If this is my target size and in order to get more sparkly I have to severely compromise on the carat size to a point that I would be unhappy- then yea. If I could find a better cut stone within my budget and carat size margins- I may keep looking.

 

[sushi]

Thanks sig, great article...

Thanks Amy... I think before I even knew about the hca I would have been happy, but now I do, I feel that I am more sure I won't get ripped off...

So in answer to have I seen them, yes but I saw about 10 different pairs in different shops so I rally can't compare them and I can't remember! So I'm looking at the hca to check and also price compare.

Another question though, will the better rated hca diamonds tend to be more expensive? Or is price usually determined by the factors in the gia cert? If I tell the dealer I'm putting the details into hca, will they give me better stones, or will they not know unless they do it themselves?

Sorry for the questions, just trying to learn!

 

[ChrisES]

Can you tell us the angles on the stones?

HCA favors shallower stones, and (as I understand it) if your stones have pavilion angles of 41.0 degrees or greater HCA is no longer reliable.

 

[sushi]

Hi Chris

Actually that makes sense, as im inputting some stones and and it wont even process them... Im even more confused now.

Oh dear

 

[aoslab]

sushi, coincidentally I have faced the same question as you, however mine is with a AGS ideal cut stone, the stone seems a little cold and "lifeless" to me under the white boutique lights, and the B&M doesn't provdie any ASET/Idealscope images, so any inputs here wil be very helpful in my learning journey

Stone 1.051ct G VS2 AGS Ideal.
AGS cert# 0104046471080
Depth : 62.1%
Table : 55.6%
Crown angle: 35.3%
Pavilion angle: 40.9%
cutlet : Pointed
Measurements 6.49 x 6.52 x 4.04
HCA: 2.7 - Very Good - Worth buying if the price is right
Light Return Very Good
Fire Very Good
Scintillation Very Good
Spread Very Good

 

[0-0-0]

If you are shopping in person, I suggest just trusting your eyes as long as you have multiple well cut stones to compare against each other.

Keep in mind that the HCA only considers 4 averaged and rounded numbers from the reports. It'll not be able to tell you much about the minor differences that you may see in person.

Here's an example of 2 stones from JA with nearly identical numbers per the reports, but IMO it's pretty obvious from the images that they'll likely look noticeably different in person: [URL='https://www.pricescope.com/community/threads/32k-budget-should-i-pay-for-color-or-clarity.171556/page-2#post-3122311#p3122311']https://www.pricescope.com/community/threads/32k-budget-should-i-pay-for-color-or-clarity.171556/page-2#post-3122311#p3122311[/URL]

 

[aoslab]

Thanks thbmok, I did a little reading up on HCA at www.diamond-cut.com.au.. and get a little better idea already.