Learn About Diamond CertificationCertification
is the key to selecting a quality diamond at the lowest price. Certification
is your only assurance of quality. A diamond certification is a detailed diamond
quality report issued by an accredited independent gemological laboratory. The
most recognized gemological laboratories that provide certified diamond quality
reports to the diamond and jewelry industry are listed below. Click on the links
to learn details about each laboratory and report.
Certifications verses appraisals: It is very important to understand that
appraisals are often not as accurate as a certified diamond quality report
performed by an independent gemological laboratory. Appraisals are only as
accurate as the skill, knowledge and training of the appraiser.
There is
currently no legal educational or training requirements one must have to
appraise diamonds or jewelry. Appraisals can be done by anyone, even someone
with no training. Appraisals are often done by the salesperson selling the
diamond. If you read the fine print, virtually all appraisals include legal
disclaimers to protect the appraiser from legal recourse if the appraisal is
inaccurate. Disclaimers usually state the appraisal is no guarantee of quality
and is only the opinion of the appraiser. Many people who buy uncertified
diamonds usually pay to much. What often appears to be a unbelievable low price
usually turns out to be a diamond that has been inaccurately graded. It is not
uncommon for a diamond appraisal to be inaccurate by two, three or more grades
when the diamond is sent to G.I.A. for accurate evaluation.
The quality
of the certified diamond reports can vary somewhat depending on which
gemological laboratory that performs the analysis and certification. It is
important to be understand that grading accuracy is not always consistent
between gemological laboratories. The color and clarity grading of diamonds are
assigned by highly trained Graduate Gemologists using there individual
subjective judgment skills to assign the proper diamond grades during analysis.
Because of individual judgment some inconsistencies may occur in assigning
quality grades. These inconsistencies are often the result of diamonds
which are on the line between two grades. Fortunately diamonds are rarely vary
more than one grade between gemological laboratories. The primary geological
laboratories that provide certified quality reports are described below.
G.I.A. - The Gemological Institute of America: G.I.A.
is the most well known and respected laboratory in the world. The division of
G.I.A. which is responsible for the certification of diamonds is G.I.A.'s Gem
Trade Laboratory. The G.I.A. diamond quality report provides a carefully
drawn plot which illustrates the exact position, size and shape of every
internal inclusion and external blemish a diamond possesses. G.I.A. is extremely
strict in assigning color and clarity grades. If a diamonds quality is on the
line of the next higher quality grade G.I.A. will usually always assign the
lower grade. G.I.A. uses a Sarin proportion analyzer, a computer electronic
measuring device to determine diamond proportions. Sun Jewelry recommends
selecting a diamond with a G.I.A. Diamond Report or A.G.S. Diamond Certification for the best
comparison of diamond quality. The cost of a G.I.A. or A.G.S. diamond
quality report is $100 to $200. G.I.A. has recently added a new Dossier
certification, a miniature version of the standard full G.I.A. diamond quality
report except it does not provide the plot that shows inclusion and blemishes.
However, G.I.A. does laser inscribe the edge or girdle of the submitted diamond
with the G.I.A. diamond quality report number for identification purposes. The
Dossier diamond quality report is primarily used on smaller diamonds because it
is lower in cost.
View a G.I.A. Diamond Certification
G.I.A. Certified
Diamond Reports provide this information:
- Shape
- Measurements
- Weight
- Depth
Percentage
- Table
Percentage
- Girdle
Thickness
- Culet Size
- Polish
- Symmetry
- Clarity Grade
- Color Grade
- Fluorescence
- Comments
about Diamond
- Plot of
Internal and External Inclusions
A.G.S. - American Gem Society (DQR)
Diamond Quality Report ,and (DQD) Diamond Quality Document are the best
certified diamond quality report available today. The A.G.S. gemological
laboratory is equal or more strict than G.I.A. The A.G.S. diamond quality report
also provides a carefully drawn plot which illustrates the exact position, size
and shape of every internal inclusion and external blemish a diamond possesses.
The diamond quality report provides a complete full analysis of diamond
proportion, color and clarity. The A.G.S. is the only gemological laboratory
that assigns a cut grade as a numerical value between 0 and 10. The AGS system
of defining cut grade is modeled after the Towkowsky theoretical ideal brilliant
which is a standard of ideal proportions and facet angles that were
mathematically calculated by Marcel Tolkowsky in 1919. It also carefully
considers important aspects of diamond polish and symmetry in the assignment of
a cut grade. An ideal cut diamond is assigned A.G.S. cut grade 0. Small
incremental proportion deviations from the ideal cut model assign the next
higher numerical cut grade. Cut grades 1 and 2 are still considered very fine.
Fewer diamonds are available with AGS diamond quality reports. AGS quality
reports are most often used by diamond cutters who wish to confirm near ideal or
ideal cut diamonds. The A.G.S. grading laboratory director is Peter Yantzer,
past founding director of G.I.A.'s Gem Trade Laboratory. The A.G.S. was
founded by Robert Shipley the founder of G.I.A.
View a A.G.S.Diamond Quality Report
Learn A.G.S. Cut Grade Guidelines.
A.G.S.. Diamond
Quality Reports provides this information:
- Description
- Shape and Cut
- Weight
- Measurements
- Depth
Percentage
- Pavilion
Depth Percentage
- Table
Percentage
- Crown Angle
- Crown Height
Percentage
- Pavilion
Angle
- Culet Size
- Girdle
Thickness
-
Polish/Symmetry
- Clarity Grade
- Color Grade
- Cut Grade
- Fluorescence
- Comments
about Diamond
- Plot of
Internal and External Inclusions
E.G.L. - The European Gemological
Laboratory: E.G.L. provides a detail diamond report that is sometimes not as
strict as G.I.A. Because the art of diamond grading is a subjective science, two
different gemological laboratories may arrive at differing opinions when
assigning a diamonds color and clarity grade. E.G.L. has sometimes been known to
assign a higher grade on diamonds that have grades on the border between two
grades. G.I.A. usually will always give the lower grade. When purchasing a
diamond with an E.G.L. quality report, it is possible to receive a lower grade
if it is submitted to G.I.A. for a new diamond quality report. Diamonds with
E.G.L. quality reports that are offered for prices significantly lower than
equal quality G.I.A. certified diamonds have the greatest chance of not matching
if submitted to G.I.A. for a new quality report. E.G.L. certifications are often
reliable but one must be aware of possible inconsistencies and limitations when
comparing diamond certifications between different gemological laboratories
The E.G.L.
certification however does provide more proportion information than the G.I.A.
diamond report by including the important pavilion and crown angles in their
diamond report. Be aware that plots of internal and external blemishes on E.G.L.
certifications are much less detailed than G.I.A. or A.G.S. quality reports.
Many diamonds under one carat in size are are certified by E.G.L. due to the
benefit of lower cost and faster service. E.G.L. also provides a
economically priced miniature version of its full certification.
View a E.G.L. Diamond Certification
E.G.L. Certified
Diamond Reports provide this information:
- Shape and Cut
- Measurements
- Weight
- Depth
Percentage
- Table
Percentage
- Crown Angle
- Pavilion
Angle
- Girdle
Thickness
- Culet Size
- Polish
- Symmetry
- Clarity Grade
- Color Grade
- Fluorescence<br
- Comments
about Diamond
- Plot of
Internal and External Inclusions
I.G.I. - The International Gemological Institute: I.G.I.
provides a detailed certification that is not as strict as G.I.A. Like the E.G.L.
the I.G.I. certification also provides more information than the G.I.A. diamond
report by including the important pavilion and crown angles in their diamond
report. Diamond grades rarely vary over one grade from G.I.A. Like E.G.L.,
I.G.I.'s diamond report cost less and is used mostly by diamond cutters
for smaller diamonds although larger diamonds are also available. You must be
aware that diamonds graded by E.G.L and I.G.I. can be less in price than
diamonds graded equal by G.I.A. and may sometimes not match G.I.A. if
resubmitted.
View a I.G.I. Diamond Certification
I.G.I. Certified
Diamond Reports provide this information:
- Description
- Shape and Cut
- Weight
- Measurements
- Depth
Percentage
- Table
Percentage
- Crown Angle
- Pavilion
Angle
- Culet Size
- Girdle
Thickness
-
Polish/Symmetry
- Clarity Grade
- Color Grade
- Fluorescence
- Comments
about Diamond
- Plot of
Internal and External Inclusions
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