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JohnQuixote, on Wednesday, Aug 22 2007, 11:17 AM, said:
barry, on Tuesday, Aug 21 2007, 07:13 PM, said:
Martin;
Two points:
1. The Tolkowsky Ideal encompasses a range in which it has been demonstrated that there is no absolute uniformity in light performance and that variance, sometimes significant, does exist.
2. The HCA, by the clear advocacy of its inventor is not a "Pick" tool but a "Reject" tool which can eliminate a large segment of poor to mediocre cut diamonds from purchase consideration. The HCA formula evaluates only 17 of the 58 facets that comprise the round brilliant shape and the 41 facets that are not analyzed can critically affect the face up appearance and sparkle of the diamond, depending on their facet angle, size, and proper alignment.
Two points:
1. The Tolkowsky Ideal encompasses a range in which it has been demonstrated that there is no absolute uniformity in light performance and that variance, sometimes significant, does exist.
2. The HCA, by the clear advocacy of its inventor is not a "Pick" tool but a "Reject" tool which can eliminate a large segment of poor to mediocre cut diamonds from purchase consideration. The HCA formula evaluates only 17 of the 58 facets that comprise the round brilliant shape and the 41 facets that are not analyzed can critically affect the face up appearance and sparkle of the diamond, depending on their facet angle, size, and proper alignment.
3. A diamond with 'ideal' light performance from the AGSL has been judged based on the output of all facets combined. This is a good pedigree if you like. Be aware that there is a range of different 'looks' even inside that pedigree.
4. When buying sight-unseen there is no substitute for a professional who actually has the stone in-hand (some don't
), who will provide photos and in-house light performance assessment and - most importantly - you feel is trustworthy enough to be an advocate in finding a superior stone for you. This may be a seller, an appraiser or combo of the two. It never hurts to have good return periods and long-term policies like trade-in/trade-up.5. Louping and scoping a diamond in live shopping situations is cool - those are the only views you see online (and usually never in stores) so it's fair to compare - but remember your eyes are your most useful tool. You need to use them to view a diamond in several different lighting conditions, not just under jewelry store lights.
6. One day I hope my beard looks as distinguished as Barry's.
Hey John,
Re: 6.
Do you like my beard too?
You do realize that my Dad's beard (Barry) looked very much like mine...many years ago
