HCA vs ImageScope vs BScope

[motcs]

What is most important in judging a stone''s cut online -- HCA numbers, ImagesScope, or BrillianceScope? I''ve seen various stones where these numbers/image qualities are not consistent. For example, one stone might have higher HCA, but lower BScope vs another stone. I know that we''re supposed to use these tools in conjunction with one another as well as with other tools (e.g. jeweler''s eye), but is there some ranking of which is most important when judging cut?

I''ve seen one stone with an HCA 1 ex-ex-ex-ex with borderline H/VH BScope scores, whereas another stone has an HCA 1.5 ex-vg-vg-vg with off-the-chart VH+ scores. I''ve read that a BScope can be calibrated to produce favorable results, so how accurate are their readings? BTW, I''m not suggesting any PS vendors would do anything like this to compromise their integrity.

Thoughts?

 

[strmrdr]

bscope: gog and rockdoc are the ones id trust to set up and calibrate their machines right. Anyone else Im a little leary of.

hca: deals with just a small subset of the properties of a diamond so there are a lot of other things that could be off and still get a good hca score.
Its at best a way to lower the number of diamonds needed to be looked at to find an awesome one.

IS: again weeds out the dogs but telling the difference between 2 top stones its less usefull expecialy if they are from different vendors.
I see it like the hca as a tool to remove the ones with large errors.

That is one reason a combination of these things is needed and not just one.
Tight sarin measurements + great looking h&a + hca score < 2 + no problems noted in the iscope image == awesome diamond :}

Tight sarin measurements + great looking h&a + high bscope scores == awesome diamond.

 

[Superidealist]

I think this is a hard time for the educated consumer. There are so many cut grading methods and devices and so many new patented cuts claiming to be better than the traditional round brilliant that it's difficult to process it all. Hopefully this will settle down a bit when the major labs roll out their new grading systems. Meanwhile, I think it's not unwise to follow the Diamond Talk mantra: Find a vendor who recognizes a beautiful diamond on sight and whom you trust and have them help guide you through the process.

 

[mdx]

I like the combination of HCA and Ideal Scope images. This is why

The laws of optical physics suggests that max visual performance in a diamond is a interwoven combination of lustre, light refraction, total refection, color dispersion and scintillation. Optimum performance is based on precise calculations of angles and planes.
We have found that if one reverse calculates a HCA score using ray tracing and based on the known laws of refraction and reflection that applies to a diamond, then the HCA appears to be extremely accurate albeit in a 2 dimensional plane.

While the HCA does not consider the minor facets and assumes a medium girdle a balanced opinion can be gained by reading the HCA together with Photo Ideal Scope images.
This combination should give you enough data to eliminate most poor performers.
Then
A reputable vendor with a good return policy that would allow you some time to take delivery and see for yourself and obtain professional opinions would be a good strategy

Johan

 

[Garry H (Cut Nut)]

Thanks Johan.
Compared to a few years ago consumers now have so many ways to grade a diamonds cut quality, and the good news is this has led to diamonds with superior cut to those of decades ago.

There are many good and interesting tools available to you, but none is the bees knees. We are working on the simple solution, but please remeber that with what you have at your disposal, you are assured to find a beautiful diamond for a little extra effort.

BTW Johan HCA does factor in girdle thickness, it is just that you need to go to extremes to notice a difference because the girdle has little effect on beauty (but more on spread).