Diamond Diameter -- Need help

[PrincessBride]

I hear everyone speaking of diamonds with such expertise. All I know is the 4C''s, but it seems to extend lots further than that. I''m looking at a .80 carat diamond with the diameter being 5.94. I don''t remember the depth. It is a size diameter considering the carats?

Also, I hear many speaking of HCA and H&A, what are they?

Thanks.

 

[RockDoc]

Date: 1/12/2005 8:36:23 PM
Author:PrincessBride
I hear everyone speaking of diamonds with such expertise. All I know is the 4C''s, but it seems to extend lots further than that. I''m looking at a .80 carat diamond with the diameter being 5.94. I don''t remember the depth. It is a size diameter considering the carats?

Also, I hear many speaking of HCA and H&A, what are they?

Thanks.

The diameter of the stone, tells a lot about it.

There are two diameter measurements. They represent the smallest measurement and the largest measurement. If they are far apart, then the diamond can look "out of round''. The measurements should be really close. They seldom are exactly the same. How much should they vary depends on the size of the diamond.

The HCA ( Holloway Cut Adviser ) is a program that rates the cut of a diamond after you profile specific information about the stone. It favors somewhat shallowly proportioned stones.

H&A Hearts and arrows is a pattern for a round diamond when viewed with an H&A viewing scope. On the top side are arrows and on the bottom side there are hearts. A "perfect" H&A image INDICATES a diamond will have good to excellent light performance... but this is not a guarantee.. But generally, its better to have a good image than none at all. THe images are indicitive of symmetry of the facets.If there is distortion, missing arrows, crooked hearts, then it may have a lower light performance than one that has a good image- both from top and bottom of stone.



Hope this helps,

Rockdoc

 

[Superidealist]

Here are threads on the topic of the relation of diameter to carat weight.

The "ideal" diameter for a 0.80ct diamond is about 6.03mm.

 

[PrincessBride]

Thanks everyone for answering my questions.

So, a 5.94mm on the largest diameter is small for a .80 carat diamond?

 

[JC]

I'm looking at a conversion chart as I'm sitting here typing this message. According to this chart a properly cut .80ct round brilliant would be exactly 6.00mm. A .75ct would be 5.8mm. So that 5.94mm diameter is extremely close to what's perfect. Remember, we are talking about "Millimeters". If someone can tell the visual size difference between 5.94mm and 6.00mm than they are looking too close....

 

[denverappraiser]

You can read about HCA here.
You can read about H&A here.

Both are discussed in the tutorial at the top of the page under 'knowledge'.

Neil Beaty
GG(GIA) ISA NAJA
Independent Appraisals in Denver

 

[GettingEngaged]

I''m working with princess cut diamonds. Are there ideal dimensions for princess cut, 80 - 90 points?