Diamond Grading Report (Certificate)

Diamond Tutorial

Diamond Grading Reports

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 :)

Almost all diamonds sold online, and better quality larger stones sold in the stores, come with a (supposedly) independent 3rd party grading report, or 'cert'. Reports help you ‘compare apples’ - but sadly there is no international standards body - different labs can give the same stone different grades.

Some vendors send a diamond to 2 or 3 different labs then sell the stone with the report that makes it cost the most. However the ‘market’ prices labs too, e.g. a diamond with a GIA report usually sells for more than one with the same reported grade from EGL. On-line listings show this. But if you are shopping in stores you should factor in the lower prices these 'soft report' diamonds often trade at. See Pricescope Grading Survey

GIA grading reports are the most common listed on the web (about 3/4's of all listings)

AGS Diamond Quality reports are popular with Pricescoper’s buying ‘unseen’ because that lab has a better cut grade system for rounds and a few other shapes.

IGI is the biggest lab by quantity. Most IGI graded stones are sold in stores.

EGL is also a big lab and was a global franchise until the slightly stricter American EGL split away.

HRD is a respected Belgian institution in Antwerp - a big trading center for rough and polished diamonds. HRD reports are more common in Europe and Asia.

Grading reports include these features below (the bold ones are in the Quick and Easy tutorial):
Cut
Shape
Carat weight
Color
Clarity
Dimensions
Treatments
Cut grades
Symmetry & Polish
Girdle inscriptions
Fluorescence
A unique report number
Plotting diagram
Comments
Holograms

Most Lab’s have web based online confirmation services. You will need to enter report # and Carat weight
GIA
AGS
IGI
EGL USA
EGL WORLD WIDE

Some labs offer perspex sealed reports which helps stop mix-ups but limits testing and viewing options.

There are hundreds of smaller and specialty labs, and independent appraisal services. Some provide useful extra information as a comfort or ‘point of sale’ support in addition to a report from one of the major labs above. There are far too many to list, but here are some examples.
GCAL
Gemex
Canadamark

Some stores, like Tiffany & Co. operate their own labs, or have other labs brand their grading reports. IGI and others provide a service like this for branded cuts.

Next Diamond Tutorial: Diamond Carat Weight »

Discuss Diamonds in the Pricescope Forum

GIA Diamond Grading Report (2006-Present).
Click & mouse over for a cool demo

University analogy

IGI and EGL are like large statewide universities.

GIA is Ivy League, and AGS is like the MIT rocket-science program.

A polisher or manufacturer sends each diamond (student) to the place it will get the best grade (earn more $).

The good to average go to the large universities (IGI/EGL).

The better ones are sent to the Ivy League (GIA / HRD) and a few nerds go to MIT (AGS).
Drop outs end up in a ‘program’ at a chain store or Joe's Bar & Grading Lab.

This fun analogy underplays complex factors such as a cutters specialty and client base and a dealers target market.

AGS Diamond Quality Document.

EGL-USA Diamond Certificate.