Diamond Grading Labs and Pricing

Diamond Tutorial

Diamond Grading Labs and Pricing

Basic 4C's
	Introduction
	Diamond Grading Report
	Diamond Carat Weight
	Diamond Cut
	Diamond Clarity
	Diamond Color
	Diamond Anatomy
	What to buy?
Fancy Cut Diamonds
	Fancy Shapes
	Princess Cut Diamond
	Radiant Cut Diamonds
	Emerald Cut Diamonds
	Asscher Cut Diamonds
	Cushion Cut Diamonds
	Oval Cut Diamonds
	Marquise Cut Diamond
	Pear Cut Diamonds
	Heart Cut Diamonds
	Trillion Cut Diamonds
Advanced Info
	Tolkowsky Ideal Cut
	Crown and Pavilion
	Holloway Cut Adviser
	AGS Ideal Cut
	Firescope & Ideal-Scope
	Hearts and Arrows Diamonds
	Table Size
	Fish-eye
	60:60
	Spread
	Diamond Girdle Thickness
	Diamond Culet
	Diamond Symmetry
	Diamond Polish
	Diamond Fluorescence
	Proportion Scanners
	Brilliance, Fire and Scintillation
	Diamond Glare
	Pricing & Lab's
	Treatments & Synthetics
	Investment
AGA Cut Grading
	Round Brilliant
	Princess
	Emerald & Radiant
	Marquise, Pear, Oval, Heart
	Glossary
	References
	Disclaimer
Further Reading
	Diamond Prices
	Engagement rings
	Diamonds :)

40 years ago grading reports were only done for the finest quality diamonds. But today even very low quality larger diamonds sold in Wal-Mart come with a cert. Demand for skilled graders is intense. The most skilled grade higher quality stones, and since grading is a human skill, accuracy is an issue.

The GIA and HRD are not for profit organizations and are often perceived to be the most independent. The AGS lab is half investor owned, and half owned by an association of up market jewlers. AGS specializes in grading better cut round diamonds and this is why AGS stones are the most expensive. The other labs are privately owned.

Imagine a cutter or merchant might send a stone to GIA if it is a certain VS2. A soft VS2 may go to another lab hoping that they may pass the stone as a VS2 (a GIA SI1 would sell for less). Pricescope challenge all labs to fund an independent survey (we would supervise) to compare various lab grades.

See results of Pricescope' independent Diamond Grading Laboratory Survey conducted in April-June 2004.

Data for July, 2004
% Price difference compared to GIA better cut rounds	Rounds Ex/Ex Pol/Sym 59% - 63% Depth 53% - 58% Table	All Rounds	All Fancies
GIA	0%	-5.7%	-15.7%
AGS	+6.5%	+5.5%	-
EGL-USA	-9.1%	-14.8%	-18.5%
EGL (Overseas)	-13.0%	-17.3%	-21.4%

Merchants send stones to AGS that they believe will get a cut grade AGS 0 or 1 (on a scale of 0 to 10). Stones with lower AGS grades are rare. But diamonds with other certs can also score very high on HCA and not all AGS 0�s score excellent or very good. Merchants may have volume deals with one or two labs; they may never send stones to AGS. It is common to have an AGS cut grade supplied by the dealer on better cut diamonds certified by other labs. This is commonly in the form of a 2 x 1 inch label stuck onto the �paper� the diamond is stored in. The diamond has not been sighted by AGSLab, the stone has been Sarin or Ogi scanned by the vendor. The information is usually accurate.

EGL invented the SI3 grade which brings them extra grading business for better I1�s and stones the dealers think might be border line SI2 / I1�s. With a close look you can usually spot inclusions. EGL-USA has a legal trademark battle raging with EGL, who operate mainly in Israel and Belgium. EGL has a reputation for softer grading while the US / Canadian owners have tightened up (which is reflected in the pricing comparison). EGL-USA certs are clearly labeled as such, but on internet data bases it is difficult to tell which is which without viewing a copy of the actual scanned cert (not a dummy web form).

HRD is the Belgian equivalent of GIA. HRD certified diamonds are more common in Europe and the East.

Populations of HRD and IGI graded diamonds on the internet are too small to make a price comparison, but in the trade round diamonds they have graded may be similar to GIA and EGL-USA respectively.

The AGA lab is a small regional east coast respected firm. They specialize in fancy shape diamond cut grading.

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