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Why does it have to be SO complicated ??

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m2001

Rough_Rock
Joined
May 8, 2003
Messages
9
Most of the websites that I search, show only:
dimension: a x b x c
depth percentage
table

None of then show Crown and Pavilion, even if they are GIA certified. Because of this lack of info, I''m unable to use Holloway Cut Adviser to determine the cut quality.

How do I determine the quality using just the dimension, depth and table ?

This is turning out to be a nightmare and confusing experience .. help PLEASE.
 

Richard Sherwood

Ideal_Rock
Joined
Sep 25, 2002
Messages
4,924
I would suggest going with vendors that make it easy for you and supply this kind of information, and more.

There are several who frequent this forum that do. Not only do they give you that info, they also supply full Sarin reports, BrillianceScope reports, IdealScope images, pictures of the inclusions, professional critique, etc, etc, etc.

I would name a few, but as an independent appraiser I'm supposed to remain impartial.

Hey, would somebody tell this fellow who the good guys are? Thanks.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
15,320
Ever tried to compare bank loans or cell phone contracts?

All industry's find ways to confuse consumers into not knowing what is wrong with their products.

Truth is less than 5% of all diamonds in the world will score less than 2 on hCA, so why would anyone want you to know they sell poorly cut diamonds?
 

Sissy77

Rough_Rock
Joined
Mar 8, 2003
Messages
16
I only know that goodoldgold.com has this kind service and that's why
it is my favorite website here.

Does anybody know some other vendors also have that?
Please help us! thanks a lot!
 

Mara

Super_Ideal_Rock
Joined
Oct 30, 2002
Messages
31,003
Okay here are the sites that list crown and pavilion angles on most if not all of their stones. Some also have closeups of the stones, Hearts and Arrow images, idealscope image, brilliancescope images, etc etc.

Goodoldgold.com
Whiteflash.com
Superbcert.com
UsaCertEd.Com
DiamondOptics.com
NiceIce.Com

There may be more but those are the ones that I recall!!
Have fun, you will start to go blind looking at all the fun reports and numbers. My favorites are the images, like the idealscope, h&a and also the brilliancescope pictures. Amazing. After surfing these sites you will not bother to go back to the ones that don't offer this information, as these sites make it way too easy for you to find a stone that performs well on the IS, the BS and the HCA!
 

pqcollectibles

Ideal_Rock
Joined
Feb 22, 2003
Messages
3,441
Leonid, one of the site creaters/experts, posted equations to convert %'s into degrees. It's not totally accurate, but veeerrry close.

In Windows, click view on the calculator and select Scientific.

Crown Angle = ATAN(2xCrownDepth%/(100-TableSize))
Pavilion Angle = ATAN(PavilionDepth%/50)

ATAN is the Inverse of Tangent. Do the math inside the parenthesis, then check the INV box and click TAN to get the answer.

Example (Just made up for example purposes):
Table 57%
Depth 62%
Crown 15%
Pavilion 44%

CrownAngle = ATAN(2x15/(100-57))
ATAN(30/43)
ATAN(.69

check Inv box, click Tan
CrownAngle = 34.9 degrees

PavilionAngle = ATAN(44/50)
ATAN(.8

check Inv box, click Tan
PavilionAngle = 41.35 degrees

Now you have the info you need to use the Cut Adviser for a close estimate of the true HCA rating.

The Example diamond rates:
4.8 HCA
Good Light Return
Fair Fire
Fair Scintillation
Very Good Spread
Comment: Good, only if price is your main criterion.

Hope this helps!
 

pqcollectibles

Ideal_Rock
Joined
Feb 22, 2003
Messages
3,441
What a Brain you are, Cut Nut!

I took my diamond Cert and calculated it all 3 ways.

Actual HCA, using Sarin was 1.2 TIC Ex/Ex/Ex/VG

HCA using %'s was 0.7 TIC Ex/Ex/Ex/VG

HCA using Angles Calculated from %'s was 0.6 TIC Ex/Ex/Ex/VG

So going through all that math does not really get you any closer to the true Sarin HCA. Many THANKS, Leonid!


I thought if Leonid posted it, it MUST be right. LOL I certainly won't be giving out that info again.


Many thanks, Cut Nut, for catching the error of the equations!
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
15,320
He is a kinda shy guy pQ, but let me boast for him


He has a PhD in materials science and he is a math wizz.

Strangely he also has a brilliant creative and marketing orientated mind.

Unlike many pure scientists, he is very tolerant and a genuinely caring and nice guy.
As you can tell, I like him

Except he ski's better than me
 

pqcollectibles

Ideal_Rock
Joined
Feb 22, 2003
Messages
3,441
Leonid, Dear Leonid~

Without you none of this (Price Scope) would be possible! I was only kidding around by sticking my tongue out at you.

We know all too well about "pure scientists". Hubby works in pharmaceutical R&D, and I spent years in Beverage Alcohol and Foods Research. Sometimes those folk get so absorbed in their work and the science that they can't even carry on a simple intelligible conversation like, "Good Morning."

Anyway, Leonid, I was just kidding around. I still wuv you!


Without you and the other creators of this website, I would have made one of the biggest buying mistakes of my life. So glad I found this site. And THANK YOU for monitoring the many threads posted here. You have averted many slugfests.

M2001~
The search engine on the front page has pretty good dimensions preset to search by. The only time I got into trouble was when I tried to search by price. Quality as the main consideration gives a choice of some of the best diamonds available. Quality and price, gives a nice mix of choices. Price as a main consideration will pull up some real dogs.

When you look at diamonds with percents only, refer to the cut chart to check the cut rating (1A, 1B, 2A, 2B, etc). When you find a diamond that is on the upper level of the cut chart that you are interested in, just call/contact the vendor for further details. I spoke with several PS Vendors and they are really nice people. If they can't get you Sarin info (most can and will) for that diamond, keep looking. Once you have the Sarin, crunch away on the HCA. (Hey I just made a rhyme. Heyjud....
)

Best of luck to you in your search!
 

Mara

Super_Ideal_Rock
Joined
Oct 30, 2002
Messages
31,003
PQ--the one thing that all 3 calculations had in common was that they were all still under 2.0..so still very excellent. .6, .7, 1.2...splitting hairs!!!

Chances are if someone does the calculation, they still get a basic idea of what the stone will perform like with the angles or Sarin. So essentially the calcs are better than nothing!

e.g. If a stone performs well across all three as yours did then it still is EX....or if a stone gives a 4.8 with calculated angles, chances are it will still be in the 4-5.5 range even with Sarin. Not the greatest.

So 4-5 for me would mean 'pass'!
 

pqcollectibles

Ideal_Rock
Joined
Feb 22, 2003
Messages
3,441
Oh Mara, you are a dear! You make me feel better, even though I still feel bad about joshing Leonid so.
I do hope he took it all in good fun!


When I was searching, I found one diamond I liked that only had %'s available. I used the HCA and the rating came out good, below 2. I posted a thread about it and one of the experts, Cut Nut maybe???, said the rating was probably off. I got the sarin from the vendor. The true HCA was over 2 and a recommended buy only if the price was good. So, I checked Price Stats and that particular diamond was priced about $450 over average.

Upshot..... HCA with %'s can be useful for screening to find better performers. Then contact the vendor for Sarin info. Rerun the HCA and get the true rating. If you find you've got a dog of a diamond, move on. If you have a great cut or a recommended buy, check the Price Stats and see how the asking price compares to the average of all PS vendors for similar carat/color/clarity diamonds.
 

Blessed

Rough_Rock
Joined
May 9, 2003
Messages
14
Hi. To get your dream diamond without a nightmare experience...use search by cut quality here. (if you REALLY want to eliminate steps, search AGS cert only--all of your cut and HCA info to plug in is right on one cert and AGS is strict and reliable (as is GIA) Simply put, if you find an AGS stone or GIA equivalent cut fine or well (as discerning as you choose) and then it scores anywhere below 2 ( I heard Garry Holloway was quoted as saying even he could not visually see the difference between a 1 and a 2 on his scale!!!)you undoubtedly will have a gorgeous diamond!!! Enjoy the hunt! Blessings!!
 

Heyjud

Shiny_Rock
Joined
Feb 26, 2003
Messages
243
PQ wrote....Once you have the Sarin, crunch away on the HCA. (Hey I just made a rhyme. Heyjud....)

Hey PQ - good for you!
Poetry is contagious too

No matter what you have to say
It could be verse....is the best way!
 
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