How GIA Identifies and Classifies Pearls
GIA is a leader in the identification and classification of natural and cultured
pearls. Since 1949, the Institute has developed comprehensive standards for describing
pearl quality known as GIA 7 Pearl Value Factors™ - Pearl Size, Shape, Colour, Nacre,
Lustre, Surface, and Matching.
GIA’s Pearl Reports outline the specific attributes of pearls and pearl jewellery,
including weight, measurements, growth environment (saltwater or freshwater), mollusc
type and the presence of any detectable treatments.
Pearl Identification Report
This report details the quantity, weight, size, shape, colour, origin (natural or
cultured and type of nucleation), mollusc (if determinable), environment (saltwater
or freshwater), and any detectable treatments. A digital image of the item submitted
is also included on the report. This report may be issued on loose, mounted or strung
natural or cultured pearls of any size, shape or colour.
Pearl Classification Report
The classification report includes all of the Identification Report information
as well as classifications for lustre, surface, nacre thickness and matching (if
applicable). This report may be issued on loose, mounted or strung natural or cultured
pearls of any size, shape or colour.
Inspection,Care, and Handling Procedures
GIA applies the same item identification and tracking procedures to all pearls,
as it does for coloured stones and diamonds.
Weights and Measures
Pearls are counted by hand and then weighed with an electronic micro-balance that
captures the weight in grams (mounted or strung), carats (loose), or carats and
grains (loose natural).
Identification and Classification
Recorded weight and measurements are verified. Pearl types, molluscs and any detectable
treatments are established using the state of the art testing equipment.
Colour and other factors are determined under a controlled viewing and lighting
environment, using a comprehensive set of pearl masters to determine colour, and
type-specific master sets of strands to classify lustre, surface and matching.
Report Processing and Item Return
All GIA Reports are examined and proofread to ensure high quality standards for
the client. A final inspection and testing is then carried out to ensure that the
same submitted item is returned to the client.