Step cuts verses Rounds in the HCA

[bgray]

does this have any value for step cuts? If so how does it work? Is there a program that you plug the numbers into?

 

[stone-cold11]

no, HCA is only applicable to rounds.

 

[Karl_K]

There will never be a hca for step cuts.
There are to many variables.

 

[bgray]

any numerical way to assess them?

 

[Lorelei]

Date: 10/9/2009 9:44:30 AM
Author: bgray
any numerical way to assess them?

You can use the following based on the figures strm uses ( correct me if I am wrong pal!)

depth - 70% or less

table - 65% or less

crown height 10% and above,

but do remember there are other proportion configurations that can result in a beautiful EC, and as always the final analysis requires ASET and detailed photographs.

 

[bgray]

anyone know where to find percentages for what numbers of EC ''s fall into the 1a category? Most stones I have looked at that fill most requirements are lacking in the crown

 

[stone-cold11]

ya, GIA do not measure crown height, so you will have to ask the vendor to do a sarin scan.

 

[bgray]

Date: 10/9/2009 10:33:13 AM
Author: Stone-cold11
ya, GIA do not measure crown height, so you will have to ask the vendor to do a sarin scan.

yes I know --many are fairly low. i found one with 11.2% but thats only a 3

 

[Lorelei]

Date: 10/9/2009 10:28:11 AM
Author: bgray
anyone know where to find percentages for what numbers of EC ''s fall into the 1a category? Most stones I have looked at that fill most requirements are lacking in the crown

It isn''t often if you are looking at EC''s which are not in house that this info is provided, so you would need to ask the vendor of your choice to provide this info by running a Sarin scan etc to provide this.

 

[oldminer]

If there was enough interest in the market for high performing emerald cuts, a cutting firm might get the job of developing such a stone for a large promoter-client. Or if a site holder wanted to promote such a stone they could have them cut. Such a "branded" emerald cut could have a lot of potential, but no one seems to have the mindset to give it a try, Dealers are struggling with keeping in business, and have fewer resources to apply to development than they once did. In time, it will improve, one hopes.

Until the day comes when emerald cuts are really "in demand" no one will cut 1A or !B cut types since the current demand is virtually non-existent. I think I developed just about the right proportion set for fine emerald cuts with the paremters in 1A and 1B AGA grades, but cutters have had little reason to cut them and consumers have no ability to demand what no diamond dealer has in stock. Someday, maybe.

 

[bgray]

Date: 10/9/2009 12:50:05 PM
Author: oldminer
If there was enough interest in the market for high performing emerald cuts, a cutting firm might get the job of developing such a stone for a large promoter-client. Or if a site holder wanted to promote such a stone they could have them cut. Such a ''branded'' emerald cut could have a lot of potential, but no one seems to have the mindset to give it a try, Dealers are struggling with keeping in business, and have fewer resources to apply to development than they once did. In time, it will improve, one hopes.


Until the day comes when emerald cuts are really ''in demand'' no one will cut 1A or !B cut types since the current demand is virtually non-existent. I think I developed just about the right proportion set for fine emerald cuts with the paremters in 1A and 1B AGA grades, but cutters have had little reason to cut them and consumers have no ability to demand what no diamond dealer has in stock. Someday, maybe.

so what do you think of this (i think the sarin had some troubles because the table on the GIA cert is 62)

12.42 x 8.15 x 5.09
4.89
62.5 D
62 T
girdle SL thick
culet small
Good Sym
Good Pol
Fluor None

width: 8.10
length: 12.43
len/wid ratio: 1.53
table vs girdle:.05
culet vs gird: .25
culet vs table: .24

total depth: 5.08 (62.7)
table width: 5.53 (?)(68.3)
crown height:average .93/11.5
pavil depth: average 3.95/48.7
girdle thick.:average .11/1.4

 

[Lorelei]

Date: 10/10/2009 12:14:03 PM
Author: bgray

Date: 10/9/2009 12:50:05 PM
Author: oldminer
If there was enough interest in the market for high performing emerald cuts, a cutting firm might get the job of developing such a stone for a large promoter-client. Or if a site holder wanted to promote such a stone they could have them cut. Such a ''branded'' emerald cut could have a lot of potential, but no one seems to have the mindset to give it a try, Dealers are struggling with keeping in business, and have fewer resources to apply to development than they once did. In time, it will improve, one hopes.


Until the day comes when emerald cuts are really ''in demand'' no one will cut 1A or !B cut types since the current demand is virtually non-existent. I think I developed just about the right proportion set for fine emerald cuts with the paremters in 1A and 1B AGA grades, but cutters have had little reason to cut them and consumers have no ability to demand what no diamond dealer has in stock. Someday, maybe.

so what do you think of this (i think the sarin had some troubles because the table on the GIA cert is 62)

12.42 x 8.15 x 5.09
4.89
62.5 D
62 T
girdle SL thick
culet small
Good Sym
Good Pol
Fluor None

width: 8.10
length: 12.43
len/wid ratio: 1.53
table vs girdle:.05
culet vs gird: .25
culet vs table: .24

total depth: 5.08 (62.7)
table width: 5.53 (?)(68.3)
crown height:average .93/11.5
pavil depth: average 3.95/48.7
girdle thick.:average .11/1.4

Might be ok Bgray, any images please?

 

[bgray]

might be awhile

 

[Lorelei]

Date: 10/10/2009 12:44:16 PM
Author: bgray
might be awhile

ok!

 

[bgray]

pix might take a few days-new camera software. what do people get just from the specs?

 

[Lorelei]

Date: 10/10/2009 9:24:58 PM
Author: bgray
pix might take a few days-new camera software. what do people get just from the specs?

I get that it is definitely worth getting pictures, in fact there is a lot of information to be had from the info above if one is familiar with EC's.

 

[stone-cold11]

Date: 10/10/2009 9:24:58 PM
Author: bgray
pix might take a few days-new camera software. what do people get just from the specs?

Probably just the aspect ratio, face up size, nothing more.

 

[bgray]

thanks so no numbers that look like problems?

 

[Lorelei]

Date: 10/11/2009 10:01:16 AM
Author: bgray
thanks so no numbers that look like problems?

I don't see any flags, the numbers tell that it is definitely worth getting images as the next step, that way we can see how the good grade for physical symmetry works in this diamond, faceting both actual and virtual, brightness and contrast and so on.

 

[bgray]

thanks again--i am waiting for some help loading new software so hopefully i can load pix then

 

[Lorelei]

Date: 10/11/2009 10:52:03 AM
Author: bgray
thanks again--i am waiting for some help loading new software so hopefully i can load pix then

Most welcome! I will keep an eye out for the pics, try to get them if you are taking them as clear as possible face up and a couple sideways, but for the face up views try to keep the stone as straight and still as you can so that the faceting pattern can be clearly seen.

 

[Karl_K]

Check for even patterns and make sure you don''t see any dull facets from the good sym and polish.
If viewing it unmounted look at the facets at an angle and see if one looks a bit frosted(10x loupe helps) if one does then look face up in that area to see if it is having an impact.

 

[bgray]

Date: 10/11/2009 11:43:09 AM
Author: Karl_K
Check for even patterns and make sure you don't see any dull facets from the good sym and polish.

If viewing it unmounted look at the facets at an angle and see if one looks a bit frosted(10x loupe helps) if one does then look face up in that area to see if it is having an impact.

thanks Karl--i dont see anything frosted (good descriptive) I am having trouble with the faceting in the corners. in more square-ish stones its easier but more elongated (1.52) the corners arent as obvious