Anyone holding a certified diamond usually receives a multi-page document from the Gemological Institute of America (GIA) as well. For newcomers, this report can look highly technical at first glance. Yet it follows a clear structure that becomes easy to read with a bit of background knowledge.
Structure of a GIA Report
At the top of the document, you'll find the report number, issue date, and basic details of the stone: carat weight, measurements, and shape. Below that are the actual grading results for color, clarity, and cut, along with additional data on polish, symmetry, and fluorescence. Each category is placed on standardized scales applied consistently worldwide.
The Plotting Diagram
A central element is the graphic representation of the diamond, known as the plotting diagram. It maps the position of internal characteristics such as inclusions and external features like tiny surface marks. This diagram is unique to each stone – comparable to a fingerprint. It allows a diamond to be identified reliably even without a laser inscription.
Laser Inscription and Security Features
Many diamonds also carry a microscopic laser inscription on the girdle containing the report number. This number can be cross-checked in the GIA database to match report data with the physical stone beyond doubt. The report itself includes security features such as holograms and micro-print to make document forgery more difficult.
STIG GROUP and STIG ROCK
At STIG INTERNATIONAL, every traded diamond is accompanied by a complete GIA report. Within STIG ROCK, this report forms a fixed part of the documentation, filed together with provenance records and storage certificates. This keeps it transparent for every stone which characteristics were recorded and how they were independently verified.