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DiamCalc and Gem Advisor....worth purchasing?

Vincent Renaut

Rough_Rock
Joined
Sep 16, 2018
Messages
34
What are your guys thoughts on purchasing the DiamCalc software ($300), in order to help with finding the right diamond for an engagement ring?

If I'm going to spend $15-20,000 on an engagement ring, is the software accurate and reliable enough with judging light performance and quality of cut to justify the relatively small cost in the total amount spent on this important purchase?

With online shopping, most of the time if an ASET isn't readily available (which it isn't most of the time), you have to purchase the diamond in order for them to get it in stock to do an ASET imaging of it anyways.

Is the software accurate enough to bypass having to pay and then request a return, as well as wait up to over 1 week to get an ASET image of the diamond?
 

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OoohShiny

Ideal_Rock
Premium
Joined
Apr 25, 2014
Messages
5,860
You could purchase an IdealScope and an ASETscope yourself, so you can assess diamonds personally, but that wouldn't remove the need to ship back and forth unless you're shopping locally and using ASET/IdealScope/HCA to choose stones.

I don't believe DiamCalc would be any use in terms of finding a diamond, as I believe you have to enter all the relevant information on angles/facets/etc., which is not always available.

I think @Karl_K would be best placed to answer this, as I think he used the software when designing the Octavia??


If you want to avoid the need to worry about ASETs and light performance and cut accuracy/consistency, you need to buy one of the 'SuperIdeals' from the PS-recommended vendors. It does remove a lot of stress and thoughts about 'could it be better??', and for some, the additional premium in cost for that peace of mind is worth it. You would also have great upgrade policies.
 

OoohShiny

Ideal_Rock
Premium
Joined
Apr 25, 2014
Messages
5,860
yes I did.

If your a diamond geek diamcalc will teach you a lot but its not needed or hugely useful to buy a diamond.
Thank you for replying, kind sir! :))
 

gm89uk

Brilliant_Rock
Premium
Joined
May 26, 2015
Messages
1,393
yes I did.

If your a diamond geek diamcalc will teach you a lot but its not needed or hugely useful to buy a diamond.
I would love to have diamcalc and play with it, but I can't afford the amount of time I would lose doing so! I understand you bought it prior to being in the trade. A lot of people here quickly have a favourite set of proportions (typically fat arrows, high crown, small table) based on looking on hundreds of online stones magnified with their appealing contrasty look, but without actually seeing many of these diamonds in real life. I suppose you must have (I assume) had an ideal favourite set of proportions as a prosumer playing with diamcalc, adjusting every variable to get your desired performance metrics. Were those favourite specs still your favourite after being exposed to lots of real diamonds being in the trade?
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
8,390
I would love to have diamcalc and play with it, but I can't afford the amount of time I would lose doing so! I understand you bought it prior to being in the trade. A lot of people here quickly have a favourite set of proportions (typically fat arrows, high crown, small table) based on looking on hundreds of online stones magnified with their appealing contrasty look, but without actually seeing many of these diamonds in real life. I suppose you must have (I assume) had an ideal favourite set of proportions as a prosumer playing with diamcalc, adjusting every variable to get your desired performance metrics. Were those favourite specs still your favourite after being exposed to lots of real diamonds being in the trade?
Actually playing with diamcalc and real world experience taught me there is no one perfect set of proportions.
At one time in my journey I was a huge fan of ~55t/34c/41p with longish lgf% and super ideal cut, I still am a huge fan of that combination as well as many others.
One of the the reasons I was a fan is that there was a cutter cutting that combination super tight and super symmetrical that more than one PS vendor carried.
The same cutter cut my wife's diamond but to slightly different numbers but super tight.
The cutter was put out if business during the De Beers supplier of choice campaign.

The more one learns the more one is not tied to one proportion set or supplier.
One of the most important things you learn is that when it comes to diamonds and diamonds proportions/performance is everything is a compromise there is never one best of everything.
For example a modern ideal cut typically compromises a little spread compared to a well cut 60/60 diamond.
Many oec diamonds were cut with knife edge girdles, today we compromise a little spread for a more safe girdle.
Modern ideal cut shifts the light performance away from candles and oil/gas lamps and soft light performance to more harsh lighting compared to an OEC. With indoor lighting shifting back to softer lighting it will be interesting to see where the compromise shifts long term.
Which brings up another thing, the compromises are not static and can and do change over time.

There are hundreds more compromises and dont get me started with fancy cuts or we will be here all day.
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
8,390
Another huge set of compromises are the tools we use.
HCA, ASET, IS, and GIA/AGS grading have a ton of compromises, some more than others but all have a lot.
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
8,390
Another compromise is turning more of the rough to dust to produce ideal cuts compared to gia EX steep deep.
 

Vincent Renaut

Rough_Rock
Joined
Sep 16, 2018
Messages
34
You could purchase an IdealScope and an ASETscope yourself, so you can assess diamonds personally, but that wouldn't remove the need to ship back and forth unless you're shopping locally and using ASET/IdealScope/HCA to choose stones.

I don't believe DiamCalc would be any use in terms of finding a diamond, as I believe you have to enter all the relevant information on angles/facets/etc., which is not always available.

I think @Karl_K would be best placed to answer this, as I think he used the software when designing the Octavia??


If you want to avoid the need to worry about ASETs and light performance and cut accuracy/consistency, you need to buy one of the 'SuperIdeals' from the PS-recommended vendors. It does remove a lot of stress and thoughts about 'could it be better??', and for some, the additional premium in cost for that peace of mind is worth it. You would also have great upgrade policies.
Are the super ideals specifically referring to round shapes?

There are hundreds more compromises and dont get me started with fancy cuts or we will be here all day.
I'm looking for an Oval.

Would you say using an ASET on diamonds in hand would be my best option?
 

iKevyn

Rough_Rock
Joined
Feb 16, 2012
Messages
13
you won't need any tools if you ask PS to help you look for a super ideal diamond :mrgreen2:. i was in your shoe at one point. i just ordered a CBI diamond which i saw in real life and it blew my eyes away. mine was a round so if you want other shape then ask away.
 

Vincent Renaut

Rough_Rock
Joined
Sep 16, 2018
Messages
34
you won't need any tools if you ask PS to help you look for a super ideal diamond :mrgreen2:. i was in your shoe at one point. i just ordered a CBI diamond which i saw in real life and it blew my eyes away. mine was a round so if you want other shape then ask away.
I saw the above poster mentioned the Super Ideal diamond from a PS recommended vendor, is a list of these vendors somewhere on the site, is there a part of the forum specifically noted for asking for a super ideal?

I've been browsing the forums and don't remember seeing a specific thread about the above.

Thanks for the input!
 

crbl999

Shiny_Rock
Joined
Jan 21, 2010
Messages
447
I saw the above poster mentioned the Super Ideal diamond from a PS recommended vendor, is a list of these vendors somewhere on the site, is there a part of the forum specifically noted for asking for a super ideal?

I've been browsing the forums and don't remember seeing a specific thread about the above.

Thanks for the input!
For super ideals check out HPD/CBI, BGD, WF ACA.
 

foxinsox

Ideal_Rock
Premium
Joined
Jul 18, 2015
Messages
2,764
For super ideals check out HPD/CBI, BGD, WF ACA.
And there's a number of threads comparing them but mostly just post in RockyTalky asking for help finding a stone that meets your preferred parameters. Most of the prosumers really enjoy shopping with other people's budgets!
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
8,390
I'm looking for an Oval.

Would you say using an ASET on diamonds in hand would be my best option?
Or work with a vendor who calls in some stones, vets them and takes ASET images for you to consider.
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,430
Are the super ideals specifically referring to round shapes?



I'm looking for an Oval.

Would you say using an ASET on diamonds in hand would be my best option?
Why do you prefer Oval cut? Shape? Spread? optical performance ?

Marquise has higher spread than Oval.
Many Fancy cuts have better Optical performance than Ovals.

please check links
1) for Spread comparison ( all diamonds from the board have same mass)
https://cutwise.com/~8Z_P
2) Board for visual comparison several fancy cuts( it is very small selection from huge variety of fancy cuts, I have not big collection yet)
https://cutwise.com/~60CG

you can not buy any of these diamonds, these links are only for education .
 
Last edited:

Vincent Renaut

Rough_Rock
Joined
Sep 16, 2018
Messages
34
Why do you prefer Oval cut? Shape? Spread? optical performance ?

Marquise has higher spread than Oval.
Many Fancy cuts have better Optical performance than Ovals.

please check links
1) for Spread comparison ( all diamonds from the board have same mass)
https://beta.cutwise.com/~96gE
2) Board for visual comparison several fancy cuts( it is very small selection from huge variety of fancy cuts, I have not big collection yet)
https://cutwise.com/~jfXj

you can not buy any of these diamonds, these links are only for education .
My girlfriend likes the shape of Ovals, however she isn't dead set on them. What fancy shapes offer better optical performance?

When I click on the first link it is asking me for a username and password?
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,430
I have not data( Dibox 2.0 movies) from August Vintage Oval. Without objective data I prefer do not share my subjective opinion .
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,581
The problem with using DiamCalc is you need to get the .stl file from the vendor and none will have a clue what you mean.
They are produced by optical scanners like Helium, Sarine, OGI etc and come in .stl .gem .srn .dmc formats.
You can never get enough data from a GIA report to make anything remotely like a useful input.
AGS have attempted to grade ovals. I have not been very impressed with their system - but it is better than being blind.
ASET is probably your best approach - images help, but having the stone inhand and a scope (you buy from me) is best.
BTW I also sell Serg's DiamCalc (declaring interests)
 

gm89uk

Brilliant_Rock
Premium
Joined
May 26, 2015
Messages
1,393
Actually playing with diamcalc and real world experience taught me there is no one perfect set of proportions.
At one time in my journey I was a huge fan of ~55t/34c/41p with longish lgf% and super ideal cut, I still am a huge fan of that combination as well as many others.
One of the the reasons I was a fan is that there was a cutter cutting that combination super tight and super symmetrical that more than one PS vendor carried.
The same cutter cut my wife's diamond but to slightly different numbers but super tight.
The cutter was put out if business during the De Beers supplier of choice campaign.

The more one learns the more one is not tied to one proportion set or supplier.
One of the most important things you learn is that when it comes to diamonds and diamonds proportions/performance is everything is a compromise there is never one best of everything.
For example a modern ideal cut typically compromises a little spread compared to a well cut 60/60 diamond.
Many oec diamonds were cut with knife edge girdles, today we compromise a little spread for a more safe girdle.
Modern ideal cut shifts the light performance away from candles and oil/gas lamps and soft light performance to more harsh lighting compared to an OEC. With indoor lighting shifting back to softer lighting it will be interesting to see where the compromise shifts long term.
Which brings up another thing, the compromises are not static and can and do change over time.

There are hundreds more compromises and dont get me started with fancy cuts or we will be here all day.
How does DiamCalc convey these compromises? Does it have a simple numeric value for fire, scintillation, brightness etc.. Can you batch a few thousand different proportions at a time and see which come on top in various categories? Maybe input an excel sheet of rows to process

Or do you have to interpret things such as the virtual ETAS included to have an interpretation worth considering?
 
Last edited:

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,430
How does DiamCalc convey these compromises? Does it have a simple numeric value for fire, scintillation, brightness etc.. Can you batch a few thousand different proportions at a time and see which come on top in various categories? Maybe input an excel sheet of rows to process

Or do you have to interpret things such as the virtual ETAS included to have an interpretation worth considering?
Public Diamcalc versions have not not modern Fire, Brilliancy metrics. We stoped upgrade metrics in public Diamcalc versions several years ago. Diamcalc mainly calculate subjective Brightness instead Brilliancy.
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
8,390
How does DiamCalc convey these compromises? Does it have a simple numeric value for fire, scintillation, brightness etc.. Can you batch a few thousand different proportions at a time and see which come on top in various categories? Maybe input an excel sheet of rows to process

Or do you have to interpret things such as the virtual ETAS included to have an interpretation worth considering?
Its interpretive, then cutting to confirm.
The hardest part is actually designing a cutable design.
There has to be enough leeway in the allowable angle sets to make it able to be produced with the performance you want.
If a design needs exact angles to .01 degrees on every facet its not going to be cutable by anyone.
 

ChristineRose

Brilliant_Rock
Premium
Joined
Aug 5, 2012
Messages
926
A round always has the best possible light performance because it's symmetric. There's no long or short edge. With an oval the short edges have a steeper slope and the long edges have a more gradual slope. The short sides are shorter E/W and deeper, and the long sides are longer N/S and are shallower. So one edge or the other will be deeper or shallower than optimal and leak light.

This is an extreme oversimplification of course. Rounds can be horribly cut, and good cutters can do all sorts of things to maximize the oval. Colored stone cutters have developed all sorts of patterns to get particular light effects from an oval, but mostly these are not appropriate for diamonds.

All the stones with points and corners are at a disadvantage because those points dwindle away to nothing at the tip, and thin areas leak light. The upside of these shapes is that they will face up larger, since they almost always track the shape of the original rough. Most diamonds start looking like a rough princess, then they lose their corners and become smaller rounds.

Step cuts (emeralds and the Asscher) have entirely different goals for their light performance and it's apples to oranges.

Cushions have so many approaches and styles with different types of performance that you can't compare those either.

If your definition of light performance is bright white light thrown out the top of the diamond, nothing else even comes close. But that's not the only factor. An oval has it's own kind of beauty.
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,430
A round always has the best possible light performance because it's symmetric. There's no long or short edge. With an oval the short edges have a steeper slope and the long edges have a more gradual slope. The short sides are shorter E/W and deeper, and the long sides are longer N/S and are shallower. So one edge or the other will be deeper or shallower than optimal and leak light.

This is an extreme oversimplification of course. Rounds can be horribly cut, and good cutters can do all sorts of things to maximize the oval. Colored stone cutters have developed all sorts of patterns to get particular light effects from an oval, but mostly these are not appropriate for diamonds.

All the stones with points and corners are at a disadvantage because those points dwindle away to nothing at the tip, and thin areas leak light. The upside of these shapes is that they will face up larger, since they almost always track the shape of the original rough. Most diamonds start looking like a rough princess, then they lose their corners and become smaller rounds.

Step cuts (emeralds and the Asscher) have entirely different goals for their light performance and it's apples to oranges.

Cushions have so many approaches and styles with different types of performance that you can't compare those either.

If your definition of light performance is bright white light thrown out the top of the diamond, nothing else even comes close. But that's not the only factor. An oval has it's own kind of beauty.
It is possible to design and produce fancy cuts which have same performance level as well as RBC ( or may be even higher) .
For example please compare this Cushion and Well Cut RBC.
btw this Cushion had been designed with old public Diamcalc Pro version( it took several years to find and check many new facet patterns )

https://files-cdn.cutwise.com/MSS-demo/1280/MSSCUSHION10.htm
https://files-cdn.cutwise.com/MSS-demo/1280/MSSRBC13.htm
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,430
Its interpretive, then cutting to confirm.
The hardest part is actually designing a cutable design.
There has to be enough leeway in the allowable angle sets to make it able to be produced with the performance you want.
If a design needs exact angles to .01 degrees on every facet its not going to be cutable by anyone.
I do not believe that accuracy 0.01 degree is necessary for fancy cuts even with 10-30 internal reflections because even big facets( with min size 0.5 degree) have diffraction angle 0.06 degree. Smaller facets have diffraction angle higher than 0.1. Real beam divergence angle inside diamond is much higher for real consumer light sources.

0.1 degree facet accuracy is necessary, but is possible now even for fancy cuts
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
8,390
A round always has the best possible light performance because it's symmetric
The modern ideal cut is a good to great all around cut in a variety of lighting but it is not the best in every kind of lighting.
It is not hard to say design a princess cut that in bright direct lighting and by some metrics that is brighter than a modern ideal cut.
An oec and some step cuts can be brighter in soft and diffused lighting while being close with them in most lighting.
In off axis lighting a well cut step cut, pear or oval can make them look a little anemic.
So one and so forth.
 

ChristineRose

Brilliant_Rock
Premium
Joined
Aug 5, 2012
Messages
926
It is possible to design and produce fancy cuts which have same performance level as well as RBC ( or may be even higher) .
For example please compare this Cushion and Well Cut RBC.
btw this Cushion had been designed with old public Diamcalc Pro version( it took several years to find and check many new facet patterns )

https://files-cdn.cutwise.com/MSS-demo/1280/MSSCUSHION10.htm
https://files-cdn.cutwise.com/MSS-demo/1280/MSSRBC13.htm
Thanks Serg!

Cushions are definitely not comparable to the other cuts like pear. They are more symmetric and of course were the earliest attempt to solve the corner problem by rounding the stone somewhat.

Also they have everything from an H&A cushion to extreme examples no one has heard of, and I'm pleased to learn (maybe a little surprised) that you have cut a cushion to match an H&A.
 
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