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Blog Guess What? Dispersion And Fire Aren't The Same Thing

Cerulean

Ideal_Rock
Joined
Sep 13, 2019
Messages
2,472
Fascinating point of view...

I'll start with the end.., The only (well mostly) logic marketing in the diamond industry is still based on historical methodic..., sell by weight and a lot. There are several cut options to choose from and good luck. That's the current norm!

In recent years some more specialized niches were born offering different or more value elements but mostly still catering to the usual normal mentioned above.

The industry at large is still busy pushing supply than listening to consumers for what they really want..., the genuine demand side.

Just like people understand the logic behind darkness in diamonds in a dark, unlit environments they should know that any overwhelming (of practically anything) disrupts the reality of things so does bright direct sunlight on most normal diamonds.

The beauty of diamonds is not just light performance based.., IMO, diamond material and proportional three dimensionality can offer great visuals even in the strongest sunlight. But if we are referring to 90%+ of diamonds cut in the last century, three dimensionality was not a strong point.

Interesting thoughts. I can extrapolate the marketing in the diamond industry to other direct to consumer industries - quantity of pretty much anything becomes paramount

this is a bit of a detour from my original post..

but my suspicion is that a percentage of consumers are becoming more discerning as compared to the last few decades - i have no data to support this, only a hunch - especially when i consider my millennial peers that have a growing interest in artisanal goods, ethical companies (not just environmental, but paying living wages, etc), and strong research inclination to select products b/c of availability of information - this may not always extend to diamond purchases, but for some it might

my point is that with concern for quality, comes research. it's almost as though you need to be taught how to appreciate a diamond, especially one i'd consider "artisanal" (whether it is super ideal, or an antique diamond cut by hand)

even the concept of three-dimensionality when it came to diamond performance didn't really occur to me, but now that ive read it, it makes so much sense - especially if i think of it as almost a category, or a way of assessing a diamond's traits that might not be captured otherwise

but this leads me back to the concept of "error prevention" - i noticed especially with super ideal buyers (threads titled e.g. "Do all well cut diamonds must appear dark?" sometimes a diamond may perform differently than expected, which is perceived as some kind of failure, when really it's not that at all

blogs, and even posts , like these are highly valuable!

thanks for sharing the knowledge
 

prs

Brilliant_Rock
Premium
Joined
Dec 26, 2017
Messages
1,574
The high crown comment was a nod to physics. Light on an efficient path in/out of a diamond with X-Y Table-PA and 15% crown height will separate more than light passing through the same XY with only 5% crown height, because light exiting the 15% crown has passed through more diamond material.
Great article John, thank you!

My wife has an OEC with a crown height of 18.3%, a table of 51%, and an average CA of 36.7°. We took a short video of the diamond after the crown facets had been cleaned up to remove chips and bruises. We had to retreat to a dark corner of our jeweler's office so my I-phone camera wasn't blinded by reflections from the overhead lights. I could never figure out where the color flashes were coming from in the video. Are they caused by dispersion as outlined so well in your article, or perhaps by something else?

 

John Pollard

Shiny_Rock
Staff member
Premium
Joined
Dec 2, 2020
Messages
157
Great article John, thank you!

My wife has an OEC with a crown height of 18.3%, a table of 51%, and an average CA of 36.7°. We took a short video of the diamond after the crown facets had been cleaned up to remove chips and bruises. We had to retreat to a dark corner of our jeweler's office so my I-phone camera wasn't blinded by reflections from the overhead lights. I could never figure out where the color flashes were coming from in the video. Are they caused by dispersion as outlined so well in your article, or perhaps by something else?
Thank you @prs - Fun video. Love those chunky pavilion facets.

Indeed, when a dispersive fan is wider than the diaphragm of the camera lens it works like the constriction of your pupil. That seems to be occurring where indicated below - red-yellow portions of fans entering the lens - although at 0:12 seconds there's a big surface reflection from a light source which seems to be colored similarly.

There are also internal and external reflections of colors which would seem to be in the environment. Do you recall what colors the observers were wearing?

1624037066872.png
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
16,544
Interesting thoughts. I can extrapolate the marketing in the diamond industry to other direct to consumer industries - quantity of pretty much anything becomes paramount

this is a bit of a detour from my original post..

but my suspicion is that a percentage of consumers are becoming more discerning as compared to the last few decades - i have no data to support this, only a hunch - especially when i consider my millennial peers that have a growing interest in artisanal goods, ethical companies (not just environmental, but paying living wages, etc), and strong research inclination to select products b/c of availability of information - this may not always extend to diamond purchases, but for some it might

my point is that with concern for quality, comes research. it's almost as though you need to be taught how to appreciate a diamond, especially one i'd consider "artisanal" (whether it is super ideal, or an antique diamond cut by hand)

even the concept of three-dimensionality when it came to diamond performance didn't really occur to me, but now that ive read it, it makes so much sense - especially if i think of it as almost a category, or a way of assessing a diamond's traits that might not be captured otherwise

but this leads me back to the concept of "error prevention" - i noticed especially with super ideal buyers (threads titled e.g. "Do all well cut diamonds must appear dark?" sometimes a diamond may perform differently than expected, which is perceived as some kind of failure, when really it's not that at all

blogs, and even posts , like these are highly valuable!

thanks for sharing the knowledge
There are very few actual advances in diamond cutting over the 4 decades of my involvement.
Yes there has been an increase in precision and of ways to measure and further improve '3 Dimensionality'. This started with Sarine, Firescope and others including Sergey et al and some of my tools etc. But not innovative - just normal tech enhancement. And for most of the world the attitude is "who cares". Certainly that is the approach of 95% of the trade.
Those advances have done little to change the basic cutting for weight dilemma. GIA made a slight improvement in 2006 with round diamond cut grade - because now we rarely see +65% tables. But last time I checked 72% of diamonds on B2B sites had GIA's top Excellent cut grade.
GIA still has no chance to grade fancy shapes anytime soon (unless they have concealed their provisional patents. Last time I spoke with anyone senior they were still trying the proportion route! D'oH!

De Beers 20 years ago tried to get some changes and a lot of horrid new cuts were launched to the market by their sightholders.

I have aired the possibility of a Cut design competition - and that really should be do-able now with man made diamonds. That could lead to an artisinal approach to the way rough is handled.
In case folk do not know - Yoram is really leading the way in his approach to using man made diamonds for cutting edge creative diamond shaping.
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
16,544
Great article John, thank you!

My wife has an OEC with a crown height of 18.3%, a table of 51%, and an average CA of 36.7°. We took a short video of the diamond after the crown facets had been cleaned up to remove chips and bruises. We had to retreat to a dark corner of our jeweler's office so my I-phone camera wasn't blinded by reflections from the overhead lights. I could never figure out where the color flashes were coming from in the video. Are they caused by dispersion as outlined so well in your article, or perhaps by something else?


Next time take a video of the environment too please. All around and across the ceiling. To get fire point lights work best. For brightness - near a window etc.
There were light sources providing that fire and reflections.
And make sure the finger prints are wiped off as someone might identify you :)
 
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