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re:HCA

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fire&ice

Ideal_Rock
Joined
Jul 22, 2002
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Hey Gary,

That HCA thing is fun. I was checking my appraisal for my orig engagement stone and notice crown angle & pavillion depth % was noted. I plugged it in ......scored a .5 (TIC)!

On an intersting note, I hope I did it right. I love my stone either way - and it's really bright. But, my proportions were:

Depth % 63% Table 56% Crown angle 34 degrees - pavillion depth % 42.5 none-tiny culet

My question, the depth seems awfully deep - but the stone works. Also, I am still baffeled. Why is it that I consistently pick a stone that is deeper? What am I seeing that I like? My 3 carat is in the 61%-62% range - and its shy of what the "chart" says to MM should be - mine is 9.23 mm range.

And...I love my european cut stone which is cut deep.

All three stones have Fluor - does this have any play in the fact that I like a deeper stone.

I never should go into the diamond business as I must have weird tastes.
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
F&I, Garry is skiing now (could you believe it?)!

63% depth sounds a bit too deep for these crown and pavilion... what about girdle?
 

fire&ice

Ideal_Rock
Joined
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leonid, I don't know - the depth was taken from the formula - not from what was on paper. But, if you plug the stuff in it comes up (I think) what I wrote.
 

fire&ice

Ideal_Rock
Joined
Jul 22, 2002
Messages
7,828
----------------
On 8/16/2002 5:10:31 PM

F&I, Garry is skiing now (could you believe it?)!

----------------

Egads..........97% here w/ humitity factor of 102%!.....lucky him....unless he is water skiing...but still...lucky him
 

pricescope

Ideal_Rock
Joined
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8,266
no he's really skiing somewhere in Australia :)

Anyway, if accurate, 34 deg. crown and 42.5% pavilion is a great combination :)
 

fire&ice

Ideal_Rock
Joined
Jul 22, 2002
Messages
7,828
----------------
On 8/16/2002 9:22:25 PM

no he's really skiing somewhere in Australia :)

Anyway, if accurate, 34 deg. crown and 42.5% pavilion is a great combination :)
----------------


A visual of snow is quite healthy now. The southest of USA has been Too hot, Too dry & no air movement.

I may be off on the depth - but the depth/mm = 63. Girdle notes medium to thin. He notes .70points - I think the orig. app. notes as .68 or .69 - 5.6, 5.6, 5.6 depth 3.53.

It plugged in as excellent on everthing except spread (good). Visually the stone is impressive -and I have been told such by people in the trade.

On an interesting note, I had the fortunate situation in that the cutter/wholesaler was there - he had a whole packet of 3/4 stones - all graded approx. the same. Wow, what a difference in the stones - from a 20 year old memory - I think there was about 10-15 stones. This one was not the largest carat weight - but really this one really sung. I wish I had the chance to revisited the situation - knowing a bit more about stones. It was this experience, that I realized that while certain parameters can predict a stones appearance - it's really a visual that needs to be done.

I'm still scratching my head as to why I seem to prefer deeper cut stones.
 

fire&ice

Ideal_Rock
Joined
Jul 22, 2002
Messages
7,828
HI

...for my 1c+ stone Old european cut.

How are these Crown angle 34 degree. Pavillion depth 44%.

Is this HCA only for RB? It came back as suspected because of the cut in th 4-5 range.

Visually, the stone is nice. I know the old ones weren't cut for the brillance of Mod cut. But, can you measure OEC and rate THEIR cuts side by side. I mean, does it make sense that all OEC cuts are not created equal and judge accordingly? I am asking because it is not out of the realm of possiblity for me to be offered for purchase these stones.
 

pricescope

Ideal_Rock
Joined
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8,266
----------------
I'm still scratching my head as to why I seem to prefer deeper cut stones.
----------------



F&I, 34 deg. crown angle and 42.5% pavilion depth is not a deep stone at all. On the contrary, it is just right! :)
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
----------------
On 8/19/2002 9:49:55 AM

HI

...for my 1c+ stone Old european cut.

How are these Crown angle 34 degree. Pavillion depth 44%.

Is this HCA only for RB? It came back as suspected because of the cut in th 4-5 range.

Visually, the stone is nice. I know the old ones weren't cut for the brillance of Mod cut. But, can you measure OEC and rate THEIR cuts side by side. I mean, does it make sense that all OEC cuts are not created equal and judge accordingly? I am asking because it is not out of the realm of possiblity for me to be offered for purchase these stones.
----------------


As for Old European, they are usually deeper and not as brilliant as Rounds. Old cut stones however can show a great fire.

Plus, you can appreciate their antique and unique look :)
 

fire&ice

Ideal_Rock
Joined
Jul 22, 2002
Messages
7,828
Do you think it may be that I like the fire in a stone best? But, what about the fact that according to the measurements for my RB stone I calculate a depth of 63%? Is this absolutely not right?

Thing is, I love my OEC - it has tons of life. You are correct. It is not as brilliant - but has lots of fire. It does have mod. blue flour and is a G color.

My 3 c. stone is around 61-62% depth - can't remember exactly. Is this considered too deep? I looked at stones w/ smaller depth % and they just didn't appeal to me as much. Do you think maybe they did not have as much fire - or do you just think that in these instances that the crown & pav. angles just work and that is what I am reacting to?

I know what I like. Perhaps I am just always picking the stone unbeknowst to me that have the proper angles that are a tad deeper. One absolute common thread in every stone I prefer is Blue Fluor. I just don't seem to be the normal diamond consumer.

Maybe I just have weird tastes! :appl:
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
----------------
Do you think it may be that I like the fire in a stone best? But, what about the fact that according to the measurements for my RB stone I calculate a depth of 63%? Is this absolutely not right?
----------------


How did you calculate it? Do you have the measurements?


----------------
Thing is, I love my OEC - it has tons of life. You are correct. It is not as brilliant - but has lots of fire. It does have mod. blue flour and is a G color.
----------------



Garry noticed that if a diamond returns too much white light one cannot see colored light. To see more and bigger color flashes diamond should have darker facets at certain viewing positions.


----------------
My 3 c. stone is around 61-62% depth - can't remember exactly. Is this considered too deep?
----------------


61-62% depth alone cannot be deep or shallow :) it depends on table size and crown/pavilion angles combination.


----------------
I looked at stones w/ smaller depth % and they just didn't appeal to me as much. Do you think maybe they did not have as much fire - or do you just think that in these instances that the crown & pav. angles just work and that is what I am reacting to?
----------------


Perhaps you didn't see the right stone yet. :)


----------------
I know what I like. Perhaps I am just always picking the stone unbeknowst to me that have the proper angles that are a tad deeper. One absolute common thread in every stone I prefer is Blue Fluor. I just don't seem to be the normal diamond consumer.

Maybe I just have weird tastes! :appl:
----------------


:)
 

fire&ice

Ideal_Rock
Joined
Jul 22, 2002
Messages
7,828
----------------
On 8/19/2002 9:49:55 AM

HI

...for my 1c+ stone Old european cut.

How are these Crown angle 34 degree. Pavillion depth 44%.

Is this HCA only for RB? It came back as suspected because of the cut in th 4-5 range.

----------------

I know OEC were deeper w/ smaller tables & larger culet. I quess I am wondering if all OEC cuts were equal or some better than others?

If so, then would there exist an appropriate crown & pavillion angle for this specific cut? I like the OEC cut. As I have stated before, the cut is kind of like a mature women - not all perfect & sparkely....just has more depth.
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
After Garry has finally drilled the concept of Brilliance is the enemy of Fire into my thick skull, I have come to the conclusion that I prefer fire. Does this limit me to the old cuts? Does anybody know if there is a way to measure output of fire as opposed to brilliance, or any paramaters one should be looking for to ensure maximum fire?
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
You make me work too hard Garry. Now I have to go and research all the different instruments. Brilliance Scope...so many scopes and it has been so long since I had mental stimulation of this sort I am having a hard time remembering what they all are, except that the fire scope doesn't measure fire it measures brilliance....off to have a look...
You don't believe in making things easy on me do you Garry...oh well, at least it will stick. Can you please hurry up and invent a real fire scope or cut annalyisis do hickie that measures fire?
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
What about that I2see(is that it) that measures color light return, is that an option for a measurement tool that would have credible results in meauring fire?

ANd if it was...

Could you not take the avg proportions of stones of a particular cut say OEC that yeilded maximum colored light return and then come up with the best cut paramaters for colored light return in that particular cut?

Maybe you should just call me if you see something nice so smoke doen't start comming out my ears.


Is there a lab (to Garry) in my location where I could pop in and view - as a member of the public- different older cuts next to eachother?
 

Mara

Super_Ideal_Rock
Joined
Oct 30, 2002
Messages
31,003
Bscope is a good bet and also possibly finding a stone with a smaller table, slightly deeper depth. You could find something that looked good in terms of of numbers, HCA scores, reports etc but with the smaller table and higher depth....you'd definitely have more fire if the angles were spot on.
 

valeria101

Super_Ideal_Rock
Premium
Joined
Aug 29, 2003
Messages
15,809
Beth,
If fire in a diamond is all you are after, why OECs? They might produce more fire, but by not being briliant enough, the stones loog great (and show off their precious fire) only under strong light (such as jewelry stores have). Otherwise, stones with low light return would just look dull - no matter how much potential they have to show fire - simply because light goes straight through instead of being reflected therough the pavilion to get difracted and show off those desirable little ranbow flashes.

All in all, you might be after a FIC (Fiery Ideal Cut) diamond, not an old cut.

Does this make any sense?
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
AHHA !!! By George that's it ! That was the thing I was trying to remember the FIC. Asked about it in another thread. Saw some info long ago on this site but couldn't find it again, and it was somewhat limited as well. I think this is maybe what Garry and the Russians are currently working on, could be mistaken. Very eagerly awaiting outcome of research though. Tell me all you know about FIC and where to find info pretty please with a cherry on top.
 

Mara

Super_Ideal_Rock
Joined
Oct 30, 2002
Messages
31,003
Run through the Pscope tutorial and find FIC information. FIC's already exist, you just have to know what to look for...smaller table, slightly deeper depth with steeper crown, but still good numbers and good FIC HCA score.




The tutorial is great for education anyway...you may want to read the entire thing.
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
Thats pretty cute Garry. I like that. I like the hot ones please.
(always wanted to use that icon). Not letting any secrets go huh. I will go and re read your tutorial. What is your preference? What is on DW hand Garry? You cut nut you. It would be very interesting to see what you have chosen for your beloved.
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,518
----------------
On 1/27/2004 10:32:46 PM valeria101 wrote:

Beth,
If fire in a diamond is all you are after, why OECs? They might produce more fire, but by not being briliant enough, the stones loog great (and show off their precious fire) only under strong light (such as jewelry stores have). Otherwise, stones with low light return would just look dull - no matter how much potential they have to show fire - simply because light goes straight through instead of being reflected therough the pavilion to get difracted and show off those desirable little ranbow flashes.

All in all, you might be after a FIC (Fiery Ideal Cut) diamond, not an old cut.

Does this make any sense?----------------

I disagree
1) If you want receive FIRE you must lose LR
2) If stone has a lot of Fire, LR( and Brilliance) is not very important for beauty
3) LR is important for close distance observation only. For far distance Fire and Scintillation are important only.
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
Okay whoa doggies, back up two steps for the newbie, what is LR? Can you tell me what it is that I am hunting if what I really love is chunky rainbows?

Yeah leaving myself wide open there, but I understand your humor...
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,518
----------------
On 1/28/2004 6:39:26 AM Cut Nut wrote:

Sergey showed me an example - I think it was the Orloff diamond - in the diamond and gold Vaults in the red square - a very poor set of proportions for light return, but very large bold flashes of fire that attract your eye from the other side of the room.----------------
It was anonymous diamond ( near 25 ct).It is very good test for cut grading system. Orloff diamond is much bigger.
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,518
----------------
On 1/28/2004 6:44:46 AM Beth wrote:

Okay whoa doggies, back up two steps for the newbie, what is LR? Can you tell me what it is that I am hunting if what I really love is chunky rainbows?

Yeah leaving myself wide open there, but I understand your humor...----------------

LR=light return
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
Anonymous Diamond in the Russian Vaults - Garry sounds like you are in like Flynn! My passport is up to date! We could get the families together and ski? lol. Sergy?

I don't want know any state secrets here or anything, I just would like a concrete set of numbers to determine the best colored light return in a diamond that won't be a dog generally in other areas.
 

Beth

Shiny_Rock
Joined
Aug 2, 2003
Messages
267
yes yes yes, I know the ideas generally, deeper cut , smaller table, but what I am asking for here fellas and in the other thread Holloway FIC is a concrete set of figures. Is this what you are developing now? You are going to tell me to be patient? How much longer??? I have been waiting 11 years already and I would like the diamond now please!

okay okay I will go back to the blackboard and write again 100x Brilliance is the enemy of Fire....sigh

Sergy, I can see what you mean about sacrificing LR and Brilliance for fire. I viewed 8* and had heard that was the best of everything. To my eye, I saw a lot of LR and Brilliance, but I did not see the fire I need in any of the lighting conditions, so I understand, somewhat, the concept. I would just like to put a name to what I am seeking.
 
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