GCAL Certification

The Essentials You Need To Know When Purchasing and Caring For Your Diamond.

Gem Certification and Assurance Lab

The Gem Certification and Assurance Lab (GCAL) is a diamond research and identification laboratory formed in 2000 by Donald A. Palmieri. GCAL is the first U.S. diamond and gemstone grading lab to earn the ISO 17025:2005 accreditation, meaning that it conforms to recognized international standards for accurate and reliable grading. In addition to evaluating and grading the diamond's color and clarity, GCAL also performs what they call a Direct Assessment of Light Performance. This Direct Assessment of Light Performance captures, measures and records each diamond's individual light performance, providing an optical symmetry and brilliance analysis score. GCAL is the only diamond grading lab to offer a Guaranteed Grading, providing cash back for any error in grading or identification.

Grading Lab Information

Information Documented in the Diamond Grading Report

Term	Definition
Shape and Cutting Style:	Shape and style of cutting.
Measurements:	Dimensions and proportions in millimeters as measured by an optical measurement device.
Carat Weight:	Weight in carats measured by an electronic micro-balance.
Color Grade:	Color assigned as compared to the standardized (D - Z) color grading system when viewed in a controlled environment by several graders. Grade is assigned when a consensus has been reached. Fluorescence, if present, and its intensity is noted below color.
Clarity Grade:	Clarity assigned as compared to the standardized (IF - I3) color grading system. Grade is assigned when a consensus has been reached among several graders.
Polish:	A grade (Excellent, Very Good, Good, Fair, Poor) assigned to the diamonds surface smoothness.
External Symmetry:	A grade (Excellent, Very Good, Good, Fair, Poor) assigned to the shape, alignment, and placement of the facets in relation to each other.
Optical Brilliance:	The overall return of light to the viewer. The report features a brilliance image with white areas representing regions of light return and dark-blue areas showing regions of light loss.
Optical Symmetry:	A visual representation of the symmetry as represented by the diamond's proportions and facet alignment.
Comments:	Additional diamond characteristics not previously mentioned on the report.
Photomicrograph:	Actual images of the diamond under 10x magnification through the table and pavillion.
Laser Inscription:	Actual image of the laser inscription containing the unique report number found on the girdle of the diamond.
Gemprint®:	The unique optical fingerprint of the diamond as recorded by Gemprint® technology and registered at www.DiamondID.com
Proportion Diagram:	A side profile of the diamond containing its actual proportions and measurements.

Types of Reports Offered

DIAMONDID® Guaranteed Certificate

The DIAMONDID® Document provides a complete diamond grading analysis of the 4c's: the diamond's cut grade, color grade, clarity grade, carat weight and light performance (optical brilliance and symmetry). In addition, photographs of the diamond's crown (top) and the pavilion (bottom) and a Gemprint® ID are included.

View Report PDF

Cut Grade Guaranteed Certificate

The Cut Grade Guaranteed Certificate combines the light performance (optical brilliance and symmetry), finish and proportions into one cut grade. For diamonds exhibiting the hearts and arrow pattern, a photograph of the phenomenon as viewed through a gemscope is provided.

View Report PDF

DIAMONDAUDIT® Guaranteed Certificate

The Diamond Audit® Guaranteed Certificate verifies and guarantees the accuracy of another lab's grading report. Diamonds carrying this certification qualify for GCAL's "Zero Tolerance" 4C's Consumer Guarantee. The certificate also provides the added value of Optical Light Performance, Gemprint® and images of the diamond.