Teach Me!

[lulu_ma]

Yes and NO! Depending on cut quality - the shorter the ray paths through a diamond the less color will be seem face up.
Perfect rounds have very short ray paths, averaging around 2.5 time diameter.
Diamonds cut to increase color have three time avg ray path lengths.
Most fancy shapes have poor light return and so they show lower colors.
The round and cushion shown are digital and have identical material color!

I’m going to piggy back off SH’s question-why did so many old cut diamonds have face ups whiter than grade?

I’d love to know the science behind this phenomena.

 

[Garry H (Cut Nut)]

I’m going to piggy back off SH’s question-why did so many old cut diamonds have face ups whiter than grade?

I’d love to know the science behind this phenomena.

Did you see my post before yours?
That is why - less than perfect light return.

 

[lulu_ma]

Did you see my post before yours?
That is why - less than perfect light return.

I'll admit that I am confused. Super Ideal diamonds seem to face up whiter due to excellent light return. Conversely, OECs and OMCs face up whiter due to poor light return and/or short ray paths?

 

[Garry H (Cut Nut)]

I'll admit that I am confused. Super Ideal diamonds seem to face up whiter due to excellent light return. Conversely, OECs and OMCs face up whiter due to poor light return and/or short ray paths?

Sorry - I misread your post.
Old cuts that face up whiter are often from South Africa - the cape yellowish - many of which are blue fluorescent. That improves the colour you see in good lighting.
But the issue is complex. The models in this image are the same diameter and color absorption because they are virtual software modeled diamonds.

 

[lulu_ma]

Thanks for the info.

Interestingly, I was recently at Shimansky in Cape Town and tried on these two. The round is a GIA M color with faint fluoro. The oval is a IGI J color.

In person the face up color looked quite similar:

 

[Karl_K]

Smaller tables and no lower girdle facets under the table means there are fewer small virtual facets that concentrate color.
Less of a difference than crushed ice to rb but it is there.

 

[snaphappy]

Thanks for the info.

Interestingly, I was recently at Shimansky in Cape Town and tried on these two. The round is a GIA M color with faint fluoro. The oval is a IGI J color.

In person the face up color looked quite similar:

I think that's why they were just called cape diamonds in the old days. They're all quite similar to the naked eye.

Cape Town? Wow!! Have you been to the museum, is it in Kimberly? I'd kill to see the Eureka Diamond!!

 

[Garry H (Cut Nut)]

Thanks for the info.

Interestingly, I was recently at Shimansky in Cape Town and tried on these two. The round is a GIA M color with faint fluoro. The oval is a IGI J color.

In person the face up color looked quite similar:

IGI tends to be softer on colour so the difference should be slight anyway. But to see colours diffused light works best

 

[lulu_ma]

I think that's why they were just called cape diamonds in the old days. They're all quite similar to the naked eye.

Cape Town? Wow!! Have you been to the museum, is it in Kimberly? I'd kill to see the Eureka Diamond!!

I did go to the Diamond Museum in Cape Town. Unfortunately, the Kimberly mine was a 12 hour drive so I did not see the famed diamond!

 

[snaphappy]

Easy to answer questions:

When I'm seeing chunkier flashes of light from an OEC, are those flashes derived from pavilion facets/lower girdle facets?

I ask because... from the top, the facets on my "OEC" look the same as my wife's "round." I think both are transitional cuts that pre-date WWII

 

[Garry H (Cut Nut)]

Easy to answer questions:

When I'm seeing chunkier flashes of light from an OEC, are those flashes derived from pavilion facets/lower girdle facets?

I ask because... from the top, the facets on my "OEC" look the same as my wife's "round." I think both are transitional cuts that pre-date WWII

That will be the mains Snappy.

 

[snaphappy]

My wife asked me today "would a new modern round brilliant look less dark in direct sunlight than our old diamonds?"

I told her no. But then I told her I'd ask you guys to make sure.

I must admit, Gary has me curious about finding a shallow round brilliant to see what all the fuss is about!

But all rounds are going to look dark in direct sunlight if they're well cut, right?

 

[Garry H (Cut Nut)]

My wife asked me today "would a new modern round brilliant look less dark in direct sunlight than our old diamonds?"

I told her no. But then I told her I'd ask you guys to make sure.

I must admit, Gary has me curious about finding a shallow round brilliant to see what all the fuss is about!

But all rounds are going to look dark in direct sunlight if they're well cut, right?

Wrong. The better the cut the worse the darkness.
Later I will show some evidence.

 

[snaphappy]

Wrong. The better the cut the worse the darkness.
Later I will show some evidence.

No you don't need to go to all that trouble. I have your book and I'm about to re-read it. I read it very quickly the first time on the kindle and I didn't retain a lot of the info.

I think my wife was just expressing fear our old diamonds might not be as pretty as new diamonds.

So potentially, our old diamonds are less dark in direct sunlight because they're not cut as well as new RBC's! She'd actually like that.

I'm still planning on finding someone local that will show me RBC's because I've never seen one in person.

 

[Garry H (Cut Nut)]

No you don't need to go to all that trouble. I have your book and I'm about to re-read it. I read it very quickly the first time on the kindle and I didn't retain a lot of the info.

I think my wife was just expressing fear our old diamonds might not be as pretty as new diamonds.

So potentially, our old diamonds are less dark in direct sunlight because they're not cut as well as new RBC's! She'd actually like that.

I'm still planning on finding someone local that will show me RBC's because I've never seen one in person.

Here you go for those that don't have my book and might be learning

Some good diamonds look dark in sunlight

Some good white diamonds look dark in direct sunlight. Yellow diamonds look great in sunlight but white diamonds look best in shaded lighting.

www.hollowaydiamonds.com.au