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Questions about HCA and TIC index

footshooter5

Rough_Rock
Joined
May 2, 2011
Messages
30
It's getting close to that time when I'll be pulling the trigger on a stone :)

I've had some great luck with the pricescope vendors, particularly Whiteflash, who have been really helpful.

I've narrowed it down to a couple of stones, a 1.22 G VS1 with a TIC of 1.4 and a 1.215 G VS1 with a TIC of 1.5.

A local jeweler that I had initially engaged in conversation told me about a 1.26 G VS2 for a little less than what I would spend with Whiteflash, and the advantage is I can see this stone in person, but when I punched in the numbers in the HCA, it gave me a 2.6.

Could someone please (in very simple terms ;)) explain to me the differences between these stones, and what kind of information the HCA is going to provide me?

Thank you in advance!

-Gayan
 

JulieN

Super_Ideal_Rock
Premium
Joined
Jul 25, 2005
Messages
13,329
2.6 is a very good score. HCA is a rejection tool; anything over two should not be considered further if shopping online. If it's a very good price, you are shopping IRL, or it is a large/hard to find stone, then up to 3 is fine.
 

tyty333

Super_Ideal_Rock
Premium
Joined
Dec 17, 2008
Messages
22,498
Give us the numbers that you punched in to the HCA for the one that came up 2.6.
 

CedarRapids

Shiny_Rock
Joined
Aug 16, 2011
Messages
146
Don't overinterpret HCA scores. The 4-5 numbers you plug into the HCA calculator are not all the numbers that represent the totality of a diamond and it's light performance. There are lots of angles, facets, etc. to consider and HCA only looks at few things.

The HCA is simply a guide that allows you to rule out stones that are less likely (not gauranteed mind you) to perform less optimally.

This is what is said on the HCA page:

"Even though HCA grades cut more effectively than systems like the AGS, it does not yet factor in symmetry and minor facets. Having found a diamond that scores well, you should employ an expert appraiser to examine the stone. If you decide not to, then at least compare the diamond to others and/or view it through an ideal-scope.

A score below 2 (Excellent) means you have eliminated known poor performers (more than 95% of all diamonds). Your own personal preference may be for a diamond with an HCA score of 1.5 more rather than one with a lower score of say 0.5."


The best way to evaluate a diamond is to look at the diamond with the naked eye. Then a zoomed in view (e.g., loupe, microscope). Look at an Idealscope image to determine light performance (lots of pink, no or minimal white). If all checks out (eye clean, no inclusions that compromise the integrity of the diamond, good return of light back towards you), then you have a good diamond.

To make a decision on the ones you are looking at, go with the one with the best cut, the one with bigger face-up size (length and width; not carat size), the one with the better return policy, the cheaper one, the one from a vendor with a better trade-up policy, the one from a vendor where you might purchase the setting. The local jeweler who will sell you a diamond for less the WF (unusual, since bricks and mortar stores have more overhead than an online vendor) might charge you an arm and a leg for the setting and make his extra profit that way.

Finally, I am assuming that all of your choices are graded by GIA or AGS. If not, everything I wrote is moot until you are comparing accurately graded diamonds.

Good luck.
 

Amys Bling

Super_Ideal_Rock
Joined
Jun 25, 2010
Messages
11,025
Remember that your eyes are a powerful tool as well. I would view the stone in various lighting situations- see what your eyes tell you.
 

centralsquare

Ideal_Rock
Joined
Jan 18, 2009
Messages
2,201
What's the certification of the local stone? Just want to make sure you're talking apples to apples in comparing price.
 

kindred

Brilliant_Rock
Premium
Joined
Dec 3, 2008
Messages
945
You can purchase an Ideal-Scope to use when looking at diamonds in person. That will help you decide if the stone with the score above 2 is worthwhile or not.
 
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