Diamond Grading Reports


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 BOB线上娱乐|bob在线客户端 Grading Survey

BOB线上娱乐grading reports are the most common listed on the web (about 3/4’s of all listings)

BOB线上娱乐Diamond Quality reports are popular with BOB线上娱乐|bob在线客户端r’s buying ‘unseen’ because that lab has a better cut grade system for rounds and a few other shapes.

BOB线上娱乐is the biggest lab by quantity. Most IGI graded stones are sold in stores.

BOB线上娱乐is also a big lab and was a global franchise until the slightly stricter split away. Currently, EGL is going through a controversy with RapNet.

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 boldBOB线上娱乐 ones are in the Quick and Easy tutorial):

Carat weight


Cut grades

Symmetry &

Girdle inscriptions


A unique report number

Plotting diagram



BOB线上娱乐Most Lab’s have web based online confirmation services. You will need to enter report # and Carat weight

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.

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.

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

University analogy

BOB线上娱乐IGI and EGL are like large statewide universities.

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

BOB线上娱乐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).

BOB线上娱乐The better ones are sent to the Ivy League (GIA / HRD) and a few nerds go to MIT (AGS).

BOB线上娱乐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.

BOB线上娱乐EGL-USA Diamond Certificate.


Carat Weight »