Method of Survey

This survey was funded by Pricescope, including the expenses of two additional
grading reports and shipping of the diamonds. None of the surveyed labs were
made aware of the survey.

Three labs were surveyed:

  1. GIA-GTL.
  2. AGSL.

  3. EGL USA.

These three labs were chosen
because there are reasonable sized commercial data bases of pricing information
to enable cost comparisons.

Pricescope approached three independent diamond vendors:
to provide diamonds from their inventories. These
stones had already been graded by either GIA-GTL or AGSL and they were then
sent to the two other grading laboratories. The vendors were aware of the
purpose of this experiment and the need for secrecy. They knew that other
vendors would be participating in this survey, but they were not informed of
the identity of the other vendors.

In total 17 round brilliant cut diamonds were selected for the survey, but one
was inadvertently sent to GIA-GTL twice (and received different clarity
grades). They ranged from 0.6 -1.25 carat, E – J color and VVS2 – SI2 clarity
ranges. The sizes and qualities were chosen to represent frequently traded
range of diamonds. The vendors were asked not to deliberately select stones
that they considered to be border line examples or stones that in their opinion
had been “missgraded”. See Appendixes I – V for all diamonds’ details.

Each of the diamond vendors independently submitted their already lab graded
diamonds to two additional grading labs. Namely:

    selected 6 diamonds (5 with AGSL and 1
    with GIA-GTL reports) and submitted them to GIA and EGL USA

    selected 4 diamonds with GIA-GTL
    reports and submitted them to AGSL and EGL USA

    selected 7 diamonds with GIA-GTL reports and
    submitted them to AGSL and EGL USA.

All diamonds and all 3 grading
reports were then shipped to
David Atlas, GG, NGJA, ASG Accredited Gem Appraisers
Philadelphia, PA for additional professional evaluation and to review the
grading results.



« Introduction   |   Results »