Advanced Courses

Pre-registration is required. Classes that have not filled by 7 days prior to the start date are subject to cancellation. All courses are offered at the CGA classroom in Toronto, Ontario.

Everyone on the CGA property  is asked to wear a mask to help stop the spread of Covid-19 and its variants.

Current Course Offerings

  Code   Course Duration Price
  PDG Canadian Diamond Grading Course 5 days $1,895.00
  CGV Coloured Gemstone Grading and Valuation 1 day $   200.00
  PEL Practical Gemmology Lab Course 5 days $1,945.00
  GBT Gemmology Basics Theory Course 36 Hours $1,795.00
  GBL Gemmology Basics Instrument Lab Course 36 Hours $1,795.00
  GBIL Gemmology Basics Intensive Instrument Lab Course 36 Hours $1,795.00


Current Class Dates

Diamond Grading
July 22 – 26, 2024 – Toronto

Coloured Stone Grading and Valuation
October 19, 2024

Gemmology Basics Theory
TBA – Toronto

Gemmology Basics Instrument Lab
TBA – Toronto

Gemmology Basics Intensive Instrument Lab
TBA – Toronto

Practical Gemmology Lab 

Canadian Diamond Grading Course

An intensive, hands-on course which will provide knowledge and skill in the grading of colourless, round brilliant cut diamonds. Please note: this course focuses on the diamond grading process, not the identification of diamond and/or its simulants. All necessary major equipment is provided, but students should bring their own pocket instruments (which are available at reasonable cost on-site). Required course textbook may purchased separately. Class size is limited to a maximum of 8 students.


  1. None. For individuals without any gemmological or trade background it is highly recommended that they first take the Talking Diamonds and Diamond and Diamond Imitation course.


  • diamonds: their formation and physical properties
  • instrumentation for grading
  • packaging/handling of loose diamonds
  • colour grading
  • cut (make) grading
  • weighing diamonds; including nomenclature, and tolerances
  • estimation of weight from dimensions
  • grading of single cut melee
  • influence of colour, clarity, cut and weight on pricing.


Coloured Gemstone Grading and Valuation

This one-day workshop will benefit gem trade professionals, gemmology students and enthusiasts alike.

Students will learn the skills to accurately grade and value coloured gemstones. Emphasis on hands-on practice with a variety of gems of different quality will provide students with the knowledge to become confident buyers and sellers in the rapidly growing coloured stone market.


  • Colour basics
  • Munsell colour system
  • World of Colour, colour communication and grading system
  • Correct grading practice
  • Valuation principles
  • Impact of treatment on value
  • The gem quality curve
  • Marketplace pricing factors
  • The Guide wholesale pricing index

Instructor: Helmut Koenig
Course fee: $200.00 including taxes.
Note: The Coloured Gemstone Grading and Valuation Course is owned and offered by Helmut Koenig. Potential students should contact Mr. Koenig at 416-317-2480 or for more information or to register for this 1 day course.
Next session(s): October 19, 2024

Practical Gemmology Lab Course

The Practical Gemmology Lab is a 5 day course suitable for a gemmology student wanting additional practical experience prior to their exam or gemmologist who wants to refresh their skills or an individual who has completed the CGA Gem Appreciation and Intro to Gem Identification courses and wishes to further their knowledge.

The Practical Gemmology Lab course will allow participants to become more proficient with the instruments used in gemmology and will ensure they can use the equipment safely and correctly.  We practice the same procedures and identification skills used by gemmoloigists in the profession. Tools used include a Microscope, a Refractometer with RI fluid, a Polariscope with a Conoscope, a Dichroscope, a Table Model Prism Spectroscope, a handheld Spectroscope and a Loupe.

Participants will receive a Statement of Completion

Course content

  • Observations using the 10× loupe and microscope and the various lighting techniques for looking at gem materials
  • Review of gemmological instruments and their construction and use.
  • Correct use of the refractometer for faceted materials and the interpretation of results
  • Use of the handheld spectroscope and how to record and interpret results.
  • Utilisation of supporting tools such as the polariscope, dichroscope, Chelsea Colour Filter and UV light
  • The theory and practice of hydrostatic specific gravity
  • Full use of exclusive CGA Library
  • Theory behind identifying features of rough and cut gemstones

Students use these instruments to practice identifying natural and laboratory-grown gemstones, imitations and assembled stones


  • 10x Triplet Jeweller’s Loupe (students may bring their own or purchase from the CGA)
  • Gemmological Tweezers (students may bring their own or purchase from the CGA)
  • Chelsea Colour Filter (students may bring their own or purchase from the CGA)
  • Conoscope (students may bring their own or purchase from the CGA)
  • London Dichroscope (students may bring their own or purchase from the CGA)
  • Hand Spectroscope (students may bring their own or purchase from the CGA)

The CGA also recommends the text book Gem-A Practical Gemmology Handbook (students may bring their own or purchase from the CGA)

Schedule: 5-days, 9:00 am – 4:00 pm
Next Session: TBA – Limited Seats Available!!
Fees: $1,895.00 + $50.00 non-refundable materials fee = $1,945.00

Practical Gemmology Lab Course Form

Gemmology Basics Theory Course

Schedule: TBA
Time:  1-night a week for 3 hours a week for 12 weeks 6:00 pm – 9:00 pm (EST) or 3:00 pm – 6:00 am (PST)
Fees: $1,795.00
Place:  Classes held over Live and Interactive Zoom

The sessions will be live and interactive over zoom. Discussions and Q&As are encouraged for a more interactive learning. Participants will receive a Statement of Completion

Gemmology is the fascinating study of all types of gem materials –  natural, lab grown and imitation.  Gems come from every corner of the  planet and touch almost every culture in the world.  Gemmology Basics is for the student who is launching their career into the world of  jewellery fashion or gem trading, or; for the avid collector who wants to know more; or even for the person who works in a jewellery store who wants to be able to answer customer’s questions; for a budding  appraiser; and finally to the goldsmith who wants to know the physical properties of the gems they are setting.

Download CGA Gemmology Basics Course Form – EST

The professional development classes described on this page do not require approval under the Ontario Career Colleges Act, 2005.