Proof that a little knowledge is a dangerous thing....

[thelittleroo]

I''m throwing myself on the mercy of this board - - I am learning SO much about diamonds, and yet, when I think I know what criteria to base my selection on, BAM! It doesn''t appear so.

Case in point: For better or worse, I put Idealscope performance as a key criteria in selecting a bright "bling-y" stone, then went with ideal cut, and nothing lower than VG for polish and symmetry. So far, so good? My color range is mostly to I, but if a J stone has mild fluor, I would consider it as well. My clarity was down to SI2.

I found a lot of great stones on WF, and thought I had this done pat, when I cruised over to GOG and a search of their stones yielded light performance results which seemed at odds with the GIA polish/ symmetry/ cut ratings of good. Example:

http://goodoldgold.com/diamond/1634/

Now, I''m back to square one when it comes to basic criteria to sort sparkle from spit. I hadn''t considered any Good rated stones, only VG/EX/ID in the color and clarity ranges because I thought those played into the perfect Idealscope image AND light performance.

So, in my case, I guess a little knowledge IS a dangerous thing for buying diamonds online! Can anyone help a novice in understanding or developing a "grid" of basic requirements for a stone to really *sparkle* and appear larger due to the brilliance/ light?

Thanks SOOOO much. I would love to learn how to do this right!

 

[Lorelei]

LOL - I can imagine you are feeling overwhelmed, so lets see if we can simplify things a bit!

Proportion preferences vary, but look for a round with;

Table - 54- 57%
Depth - 60- 61.8
crown angle - 34 - 35 deg
pavillion angle - 40.5 - 40.9 deg
girdle thin to med/ slightly thick
polish - VG and above ( many want at least EX and Ideal although good and above is said to look the same to the untrained eye)
Symmetry - same applies as for polish

Then an Idealscope basically detects light leakage which would be unlikely with a diamond of the above proportion combos but is a good tool to use - also the HCA is very useful to help you choose your candidates.

 

[thelittleroo]

Thanks Lorelei - - I read the recent thread on HCA which helped a lot. It sounds like I have two choices finding the perfect stone: a fast-track method of only looking at ACA's (LOL! I guess you pay for 'easy' too...) or a dedicated search through hundreds of diamonds to weed out the best of the best hoping for a keeper, which carries a risk and lots of time. And it sounds like there may be professional buyers out there who may be competing for those "mis-marked" or underrated stones too.

So, once I have a stone that is ACA and/or has an HCA score of <2, is that a guaranty of light performance, or what other factors can screw that up? And regarding the light performance I mentioned in my first post, being potentially excellent on a stone with less polish/cut/ or symmetry - - is that like how the Leo diamonds score so well? They're cut differently but not necessarily a better stone?

Still learning... thanks for all the great advice and willingness to educate!

 

[Lorelei]

You are welcome!

Date: 8/4/2007 9:35:12 AM
Author: thelittleroo
Thanks Lorelei - - I read the recent thread on HCA which helped a lot. It sounds like I have two choices finding the perfect stone: a fast-track method of only looking at ACA's (LOL! I guess you pay for 'easy' too...) or a dedicated search through hundreds of diamonds to weed out the best of the best hoping for a keeper, which carries a risk and lots of time. And it sounds like there are lots of pros out there who may be competing for those 'mis-marked' or underrated stones too.

So, once I have a stone that is ACA and/or has an HCA score of <2, is that a guaranty of light performance, or what other factors can screw that up?

An ACA has to pass rigorous tests and come up to very high standards to get the ACA title, which isn't awarded easily, so you can pretty much take it to the bank that an ACA is going to be a top performer - this is one of the easiest ways of getting a stunningly cut diamond! As to guarantees, the HCA is predicting how a diamond is likely to perform based on the info given, that is where an Idealscope image and ASET come in, also use the vendor's expert eyes and then your own for the final choice! With the calibre of diamonds you are considering, not much can muck things up with these types of proportions.

Also consider WF'S Expert Selection, these have often missed the ACA title by a whisker, and can be a superb choice! Also to narrow things down, use the search by cut and in house options with the search tool as this will do a lot of the sorting out for you!


And regarding the light performance I mentioned in my first post, being potentially excellent on a stone with less polish/cut/ or symmetry - - is that like how the Leo diamonds score so well? They're cut differently but not necessarily a better stone?

Sorry - I don't know much about Leo diamonds to be able to compare those.

Still learning... thanks for all the great advice and willingness to educate!

Here you go, useful info for symmetry http://diamonds.pricescope.com/symm.asp

And polish http://diamonds.pricescope.com/polish.asp

 

[scogar]

Tell me about it brother. I am trying to do the same with a princess cut. I get on for a few days and get ideas of what I am looking for but then I ask people and it seems that I am off, so I refine my criteria and try again. It''s like I''m in a never ending circle of confusion. Good luck and hang in there. I beleive these people do know what they are talking about. I just wish I too could learn enough to be not so dangerous to myself.

Scogar

 

[Ellen]

Date: 8/4/2007 10:12:46 AM
Author: scogar
Tell me about it brother. I am trying to do the same with a princess cut. I get on for a few days and get ideas of what I am looking for but then I ask people and it seems that I am off, so I refine my criteria and try again. It''s like I''m in a never ending circle of confusion. Good luck and hang in there. I beleive these people do know what they are talking about. I just wish I too could learn enough to be not so dangerous to myself.

Scogar

If you stick to AGS0 Princess, it will take the worry out of it.

 

[Lorelei]

Date: 8/4/2007 10:14:33 AM
Author: Ellen

Date: 8/4/2007 10:12:46 AM
Author: scogar
Tell me about it brother. I am trying to do the same with a princess cut. I get on for a few days and get ideas of what I am looking for but then I ask people and it seems that I am off, so I refine my criteria and try again. It''s like I''m in a never ending circle of confusion. Good luck and hang in there. I beleive these people do know what they are talking about. I just wish I too could learn enough to be not so dangerous to myself.

Scogar

If you stick to AGS0 Princess, it will take the worry out of it.

Ditto that as Princesses are a different kettle of fish to a round.