Opal Grading Workshop

Opal’s unparalleled beauty lies in its almost magical play of colour. Opals have long been valued for their rare ability to capture the rainbow. In the first century A.D. Pliny the Elder wrote of opals:
“For there is amongst them the gentler fire of the ruby, the rich purple of the amethyst, the sea-green of the emerald, and all shining together in an indescribable union.”

Greg Kratch, a gemmologist and lapidary whose passion for opals is both unrivaled and contagious, developed this workshop for the Montreal School of Gemmology (EGM). Greg spent over ten years mining, cutting, and grading opals in Australia’s famed opal region of lightning ridge and has studied and worked extensively with opals from the new Ethiopian deposits.

Who Should Take This Course

This course is perfect for both beginners and professionals alike who are fascinated by the mystery of opals.
No prerequisites.

What You’ll Learn

During this two-day workshop students will learn about opal’s physical properties, how to identify different varieties, and how to grade opals using a system created by the Australian Opal Association. Students work with specialized reference materials and Greg’s impressive collection of opal specimens.

What You’ll Receive

Course materials include Paul Downing’s book: Opal Identification and Value that students will use during the workshop and keep as a valuable reference for the future.
Students who successfully complete this course will receive an EGM letter of completion.


Presentations and many course materials are in English only but worksheets and explanations are available in French as well.

How to Register

You can register online, by phone at 514-844-0024, or by mail.

You can also register on the French version of the page.