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What depth % and table % should I look for

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golfer

Shiny_Rock
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Oct 7, 2002
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I understand that each diamond is different, and there are lots of factors and dispute about what is the best cut.

But I am dealing with huge lists from e-merchants that just list "depth %" and "table %" instead of rating the cut (ideal, VG, etc.).

As an initial matter, what is the range of ideal depth and table %?

What is "perfect," i.e., if you were building a diamond and, what is the range of GIA/AGS ideal?
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
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8,266
Try to avoid depth >63%.

When table size increases, depth should be less. E.g. if table is larger than 58% depth should be less than 61%.

Diamonds with small table size (e.g. 53%) and 63% depth can still be ok if crown and pavilion angles are ok.
 

StevL

Brilliant_Rock
Trade
Joined
Dec 31, 1999
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598
Off Topic :)

You must be a golfer, what part of the US are you in? Do you play much? Ever play in the Southeast?
 

Rook

Shiny_Rock
Joined
Oct 4, 2002
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294
L.

I am very interested in the interrelationships between table and total depth percetages and how they complement each other as they change. Where can I find out more about this and the other relationships that make up a well cut diamond. Hopefully there is something on all diamonds, or pear diamonds and not just rounds.

Thank you,
Jeremy:))
 

golfer

Shiny_Rock
Joined
Oct 7, 2002
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I play a fair amount, usually in the mid-atlantic area.

How do the following numbers sound?

(round diamond)

depth 60.1, table 57
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
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8,266
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How do the following numbers sound?

(round diamond)

depth 60.1, table 57
----------------


Not bad.
 

golfer

Shiny_Rock
Joined
Oct 7, 2002
Messages
128
well, i realize that... but i was hoping for a "looks ideal, if everything else is in order" or a "most likely only VG" answer

thx in advance
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
----------------
I am very interested in the interrelationships between table and total depth percetages and how they complement each other as they change. Where can I find out more about this and the other relationships that make up a well cut diamond. Hopefully there is something on all diamonds, or pear diamonds and not just rounds.
----------------


Jeremy,

If you have fixed set of crown and pavilion angles, girdle and culet, changing the table size will lead to changing the crown height % (and total depth %) for round diamonds as following:

CrownHeight% = 0.5 * (100 - Table%) * TAN (CrownAngle).

:)[/u]
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
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8,266
Golfer,

It has a good chance to be ideal but can't tell more without additional info like crown and pavilion angles, you know...
 

gcallas

Rough_Rock
Joined
Dec 2, 2003
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8
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On 10/8/2002 10:53:19 AM leonid wrote:


----------------
I am very interested in the interrelationships between table and total depth percetages and how they complement each other as they change. Where can I find out more about this and the other relationships that make up a well cut diamond. Hopefully there is something on all diamonds, or pear diamonds and not just rounds.
----------------


Jeremy,

If you have fixed set of crown and pavilion angles, girdle and culet, changing the table size will lead to changing the crown height % (and total depth %) for round diamonds as following:

CrownHeight% = 0.5 * (100 - Table%) * TAN (CrownAngle).

1.gif
----------------



OK, so this is over a year old, but I was looking for info on table sizes and I came across it. Unless I'm reading the equation wrong, it doesn't make any sense. Crown height and crown angle are almost equal (low 40s, generally) and therefore "0.5*(100-table%)" would have to be close to 1 to make this work. But that would require a table % of about 98, which obviously is incorrect.

confused.gif
[/u]
 

niceice

Brilliant_Rock
Joined
Jan 29, 2003
Messages
1,792
As you pointed out, this thread is a year old, but since you recovered it to the surface of PS, we'll send the concept of buying a diamond solely off of the combination of table and depth percentage to the bottom of the ocean again... It can't be done with any predictable accuracy. Period.

If you're working with sellers who only provide the total depth and table diameter measurements, find another seller who provides the information that you are looking for. Lots of us do. The ones who don't are not able to provide the crown and pavilion angles readily on their web site because they don't actually have the diamonds in their possession. They are merely mirroring the multiple listing services available to the trade and most of the manufacturers do not list the crown and pavilion angle measurements on their inventory lists. Those of us who do provide complete proportions informaton for the diamonds listed on our inventory are able to do so because we have the diamonds in our vaults and thus are able to provide buyers with full details, including clarity photographs and discussion as to the extent and visibility of the inclusions... Want to know how visible the inclusions are from a side profile? You can't determine that off of the plotting diagram on the lab report, you need a real person to do that and not a script... Want to know whether the diamond crystal located in the center of the table facet is light or dark? You need a real set of eyes to make that determination as well... Want to know whether the diamond is truly cut to ideal proportions? Buy it from somebody who actually has it. Everything else is bunk. You may as well walk into a jewelry store and say "Nail me to the wall, I'm an idiot and I'm willing to succomb to whatever line of B.S. you want to shove down my throat... All I want is a diamond with a total depth under 61.8% and a table between 53 - 57%" and believe it, you'll get nailed. God love the people who are willing to take the extra minute to get the information required to make an intelligent decision! Those are the people who are changing how the diamond industry operates.
 
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