Discernable Differences in Diameter

[SinAZ]

Hi Everyone! If all else is equal and one is comparing two ideal cut RB stones how much of a difference in overall diameter is needed for an "average" person to start noticing the difference? Would the .25mm difference between a 5.75mm and 6.00 mm stone be noticeable? My geometry (pi*r*r) tells me that''s about a 13.5% increase in surface area.

Thoughts?

 

[Lorelei]

There will be a difference, this thread shows some ( not exact) examples but will give you a feel for various comparisons.

https://www.pricescope.com/community/threads/diamond-size-comparison.83517/

 

[oldminer]

I'm pretty certain you can readily see the size difference between 5.75mm and 6.0mm When we QC (Quality Control) merchandise for large firms most allow only 0.1mm diference in size although a couple more liberal firms say no visual difference between pairs of stones. This generally won't exceed 0.2mm in common sizes.

When one compares 1/2 carat stones, a 0.2mm size differential is noticeable, but if you compare two 3.00ct rounds you might not so easily notice a 0.2mm diameter difference. The relative size of the object to the differential in size changes as absolute size changes.

 

[oldmancoyote]

The human eye in optimal conditions is able to see differences of about 1/20 of a mm (0.05 mm). In practice it will depend on whether you have good lighting, whether the objects are side by side (i.e. visible together), whether you are really looking for the difference or evaluating other things (does it sparkle? do I like this on my finger?), etc.

Assuming equal quality cuts, shape etc. I doubt you'll be able to see the difference between a 5.75 and a 6mm set diamond while looking at them at a normal eye-to-hand distance unless you have them side by side and are specifically looking for the differences. (BTW - that's less than 9% difference in surface area, not 13.5%). Equally, I have no doubt that if you are given the two stones loose, and told one is smaller and the other is bigger you'll spot which is which reasonably easily.

Be careful of photographic comparisons. Unless they are scaled at 100% of real life, they can pretty much tell the story they want to tell.

 

[neatfreak]

Are we talking set in a ring or just general comparisons? I think it's harder to see small differences once the stone is set. But I also think that you could notice a difference between 5.75 and 6.0 if they were side by side.

 

[SinAZ]

Date: 11/17/2008 2:17:04 PM
Author: oldmancoyote
(BTW - that''s less than 9% difference in surface area, not 13.5%).

Right you are! I had mistyped a 24 instead of 25 when I was doing my math which made a big difference.

 

[SinAZ]

So I guess it''s really a matter of how one is looking at the stones. Side by side the difference could be apparent but put either stone into a setting by itself it would be hard to say which one you were looking at. Just looking at a mm measurement on a ruler and I can see why this would be difficult.

 

[honey22]

Definately in that kind of size, but not when you are looking at bigger 2ct+ stones for example.

 

[Kelli]

I got my diamond recut and it lost about a little over a tenth of a mm in diameter. It started out as 7.30 X 7.33 and now it is 7.17 X 7.21. Obviously I was never able to look at the difference side by side, but it''s so much brighter now due to a better cut that I''m not sure if I can see it or not. Sometimes I think it looks a little smaller than it used to, then other times it almost seems bigger than it was. I''ll post two similar shots taken before and after the recut. You can see the difference in the pictures, but it''s not over-whelmingly obvious. Hope this helps

 

[Kelli]

before

 

[Kelli]

after. These pictures weren''t taken at the exacty same distance so it''s hard to really tell, but here it is anyway.

 

[oldmancoyote]

Using the highly scientific method of ruler-on-screen, the ring (not the diamond) is 71 mm in the first photo and 67 in the second (your mileage may vary)

For a "home-made" shot, it's remarkable consistency, but the 6% scale difference is way greater than the 1.7% diameter difference in the diamond... The lovely cut is apparent, though!