Diamond stats

[Postie]

anyone have a link to or know stats like:

1. % Of Diamonds with the top (GIA) Cut Grading
2. % of Diamonds with from colour ranges D-H
3. % of Diamonds with strong to very strong blue fluorescence


Thanks in advance

 

[oldminer]

I think the top 2 questions you have asked are very subject to people being able to make statistics tell most any story they want.

The percent of diamonds GIA grades with top cut grades have little to do with how many finely cut diamonds actually are in inventories or for sale. It is only a relatively recent event that GIA even decided to grade the cut of diamonds at all. Different diamond sellers will have very different percentages of "Excellent" cut GIA diamonds in their inventories because they have different customers and the vast majority do not demand super fine cutting. At least, not yet. Some of the most demanding sellers of diamonds use AGSL for determination of cut quality and regard GIA's top grade as "loose".

The percent of diamonds which are available in D-H color are large because that is a sweet spot of "demand". Sellers tend to want to own and to offer the diamonds that sell easier and sooner than others. We are told that more K-Q colors are produced, but where they disappear to is a good question. There are tropical areas of the world where yellower tinted diamonds sell rather well, but the markets we are most involved in want whiter material. If you search Pricescope and get the data hidden in the volume of diamonds being offered while eliminating the many duplications, you might come up with some profile of a percentage, but Pricescope is a narrow percentage of total diamonds being sold and to a very well informed, unique type of customer still. I'd say the majority of diamonds currently sold in the USA are I/L range and graded as G/I. Confusion is king with masss marketing.

We believe less than 1% of diamonds have strong or greater long wave UV fluorescence. I wear one and I like it, but I doubt it would make a great diamond for an engagement ring. The fluorescence has a definite visual effect that I like, but many would find it a problem to explain it to their friends and family. I always have liked the strange and unusual in gems, but novices tend to cluster on the simpler solutions.

 

[John P]

Dave's comments are right-on. Stock choices reflect demand and turnover more than actual rarity, as I'm sure you realize.

IDEX did a 100-day survey of about 12 million diamonds you may find interesting.
http://www.idexonline.com/portal_FullMazalUbracha.asp?id=30649

Those findings reflect the mainstream - different than the focus and flow on PS - with one big exception: They included IGI's loose diamond grading share only, but the vast (VAST) majority of IGI's reports in US commercial markets are finished jewelry and appraisal-reports.

 

[denverappraiser]

Date: 3/27/2009 10:13:57 AM
Author:Postie
anyone have a link to or know stats like:


1. % Of Diamonds with the top (GIA) Cut Grading

Based on that IDEX study linked to above, roughly 25% of the round stones currently being graded by GIA have the top cut grade. Roughly half have ‘very good’ (the second grade).

It’s an interesting statistic but use it with care. Aside from excluding all stones graded before 2006, it excludes all stones sent to other labs or sold without papers at all, possibly because of this very issue. A GIA grade of ‘fair’ or worse is a commercial disaster and it’s the reason that the bottom two grades of ‘fair’ and ‘poor’ are effectively non-existent in the marketplace. A dealer would be better off with no report at all than to have it ‘certified’ as poor.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[John P]

Date: 3/27/2009 11:20:36 AM
Author: denverappraiser

Based on that IDEX study linked to above, roughly 25% of the round stones currently being graded by GIA have the top cut grade. Roughly half have ‘very good’ (the second grade).

It’s an interesting statistic but use it with care. Aside from excluding all stones graded before 2006, it excludes all stones sent to other labs or sold without papers at all, possibly because of this very issue. A GIA grade of ‘fair’ or worse is a commercial disaster and it’s the reason that the bottom two grades of ‘fair’ and ‘poor’ are effectively non-existent in the marketplace. A dealer would be better off with no report at all than to have it ‘certified’ as poor.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

This is the same reason that 4/5 of the reports AGS issues are for AGS0 diamonds. No one wants their diamond to have paper saying AGS5...the manufacturer will send it elsewhere.

When I last checked EGL’s Premium cut grade spanned all of GIA's EX, VG and even some G combinations. Reports from GIA and AGS have the most value in terms of reputability but a diamond with an "EGL Premium" report will likely sell faster than the same stone accompanied by AGS5 or GIA Good - and the color and clarity may read as higher to boot. Planners upstream have plenty of options. GIA reports trade at high values in nearly all markets, so will be the first choice in many cases, but not the path for all.

 

[denverappraiser]

AGS-0 means a stone is ideal cut. Yippie.

AGS-1 means the dealer thought it was ideal cut and was wrong for whatever reason. Bummer for him.

AGS-2-10 means the dealer thought it was ideal cut and was stupid.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[John P]

Date: 3/27/2009 12:17:11 PM
Author: denverappraiser
AGS-0 means a stone is ideal cut. Yippie.

AGS-1 means the dealer thought it was ideal cut and was wrong for whatever reason. Bummer for him.

AGS-2-10 means the dealer thought it was ideal cut and was stupid.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

Alternately, one can be fully aware the diamond will get a 1 (polish or sym) due to the crystal''s natural graining or other unavoidable circumstances, and yet choose to have the 0 light performance pedigree and 1 overall rather than send it to another lab.

(and mea culpa... I confess to picking nits on our behalf whereas Lord Beaty is right in the overwhelming majority of cases)

 

[Regular Guy]

Date: 3/27/2009 12:17:11 PM
Author: denverappraiser
AGS-0 means a stone is ideal cut. Yippie.

AGS-1 means the dealer thought it was ideal cut and was wrong for whatever reason. Bummer for him.

AGS-2-10 means the dealer thought it was ideal cut and was stupid.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

AGS Gold, ideal, means....(?)

 

[Postie]

Date: 3/27/2009 10:26:25 AM
Author: oldminer


We believe less than 1% of diamonds have strong or greater long wave UV fluorescence. I wear one and I like it, but I doubt it would make a great diamond for an engagement ring. The fluorescence has a definite visual effect that I like, but many would find it a problem to explain it to their friends and family. I always have liked the strange and unusual in gems, but novices tend to cluster on the simpler solutions.

Thanks for the input. I didn''t think there would be any clear cut answers, just that there may be some trade reports with these stats.

Why do you say it wouldn''t make a good engagement diamond? Be interested to hear you thoughts.

I wanted something special with a little edge so specifically sought a near colourless diamond with strong blue fluorescence.