RE: Qualitative Analysis

[nicholastanth]

1) I was told that the "crystal" of a diamond overrides the way the diamond is cut that is never mind the proportions; for instance the "Golconda" which is said to be of "purest" will display optimum scintillation - how true is this statement? Will the facets angles in this instance enhance or mar the "fire" give the leakage of light is great? Will a 10 times magnification be able to spot this variance?

2) I have seen many diamonds of similar proportions of identical colours. carat weight – clarity and with different Gem Lab reports and can spot differences in “fire”, “life”, etc – are there different standards in grading or could it be due to the quality of the crystal/rough. Which Gem Lab gives International accreditation? Why is it that a “Lazare” diamond is claimed to be “Ideal”. Does this mean that the quality of this crystal is not of importance?

3) Do fancy shaped diamonds inhibit the same factors as the rounds that is if one uses the Ideal scope or the Sarin machine, what sort of variances can one expect?

4) why are some diamonds “whiter” with stronger fluorescence for the same”grade”? can fluorescence be removed? If two identical diamonds (same colour, clarity, carat weight – one with strong blue; the other none) are tested using the Ideal scope and the Sarin machine. What can one expect assuming that both diamonds are cut in technically the same manner?

 

[mike04456]

Oh boy, where to begin?

1) This is rubbish, BS, fluff, marketing nonsense, take your pick. Whoever told you this is either hopelessly misinformed (some diamond retailers are) or lying in order to confuse you. Either way, if this person is trying to sell you a diamond, run, do not walk, somewhere else. Unless the crystal is so heavily included as to interfere with light transmission, it has nothing to do with brilliance, which is entirely determined by the proportions of the cut. "Golconda" is a old trade term that has been so misused as to be meaningless. Also, magnification is for determining clarity, not brilliance.

2) The only lab that gives a reliable cut grade is AGS. There are indeed varying standards in grading from lab to lab, but that has nothing to do with the appearance of brilliance. Two D-IF diamonds graded by the same lab may have radically different appearances because of the quality of the cutting. The most reliable labs are GIA, AGS, HRD, and ELG-USA.

Lazare pioneered the American Ideal cut but are hardly the only ones making them. The term means a diamond cut to a certain range of proportions. Ideal cut has nothing to do with the diamond crystal.

3) Fancy shapes and rounds are apples and oranges when you're talking about cut quality and brilliance. There is a lot of disagreement on what qualifies as proper proportions when it comes to fancy shapes.

4) Fluorescence is an inherent quality of a diamond and cannot, to my knowledge, be removed or reduced. It only affects the apparent color, not the brilliance. Blue fluorescence in yellowish diamonds can cancel out the yellow color to create a whiter appeareance.


I suggest you go read the PS tutorial (see link at top) before going any further. It sounds like you need to do a lot of "unlearning" of things you've been told before trying to buy a diamond. Good luck.