cut adviser

[hopeless perfectionist]

Hi guys

I've been using the cut adviser on this site to check out some diamonds and I've noticed you get quite different results for the same diamond depending on wheter you use pavillion angle or %

which is the more acurate result? and why does thos occur?

Any comments welcome

Best regards

HP

 

[pricescope]

Hi HP

HCA is based on angles because light reflections depends on angles not depth %. When you enter %’s we mathematically calculate the angle.

Sarin measures angles more accurately than depth %. If %'s are not accurate enough, HCA calculates different result.

That's why we prefer you enter crown and pavilion angle data from accurately calibrated and maintained Sarin devices operated by impartial laboratories.

EGL and HRD list depth %’s rounded to whole percentage points. Entering this data is almost useless.

Sarin Technologies and Ogi Corporation are two of the main companies who manufacture proportion-measuring devices. The base models from both companies have limited accuracy; advanced models measure more accurately and some incorporate multi-lens systems for varying sized diamonds.

The Ogi method measure dimensions best, but is less accurate for angles because it measures ‘meet points’ and ‘joins the dots’ to calculate the angles. Sarin is more accurate for HCA purposes because it measures the angles directly and ‘constructs’ the diamond. Sarin proportions depth percentages and diameters are often different to the measured parameters on certificates.

Keep in mind that Sarin measurements have about 0.1-0.2 degree accuracy. It is not worth to split hears with HCA. Just make sure your candidate have decent score.

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.

 

[fire&ice]

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On 8/17/2002 6:51:10 AM

Hi HP

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.
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Interesting about all the technology!

Why would on prefer a 1.5 than a .5. Curious as I'm the one w/ wierd preferences.