Examine gems using professional gemmological equipment provided in class. Understand the process of identification & know limitations of each tool. Discover & separate imitations, synthetics & assembled materials from natural gems.

Course outline

  1. Introduction to Equipment and Identification Process.
  2. General Observation techniques, Loupe use and Tweezer techniques.
  3. Polariscope and Dichroscope uses and practice.
  4. Refractometer Part 1, Understanding and finding Refractive Indices.
  5. Refractometer Part 2, Spot readings and Optic Character.
  6. Use of the Microscope and understanding Inclusions.
  7. Spectroscope and Diamond Tester uses and practice.
  8. Fluorescence testing, Specific Gravity and Immersion testing.
  9. Completion of testing 100 gems.

The instructor

  • Tanja Sadow

    Tanja Sadow

    Tanja is an award winning jewellery designer with more than 4 decades of experience educating the jewellery industry across 4 continents. Dean and founder of JDMIS, Tanja works with aspiring artisans as well as top jewellery brand team members to help them achieve brilliance in their careers. Read More
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  • Tools


    Like all JDMIS courses, students receive everything they need to complete all their coursework. This course includes all the tool and reference material needed in order to fully appreciate the gem exhibits and the jewellery samples.

  • Materials


    This popular course takes place in our Diamond Room where participants are able to see, examine, scope and understand Tanja's collection of over 1,200 gems, jewellery pieces and examples, including rare and valuable specimens as well as common imitations found in jewellery markets in the region.

  • Learning path

    Learning path

    This course is a Core Component of all learning paths. We refer to these modules as CC.

    GT100 - Jewellery Trade Practices 1: Gem and Jewellery Trade Secrets

    Next Step (Advanced Jeweller's Knowledge):
    FT200 - Jewellery Fashion Trends 2: Aesthetic Self Discovery and Future Trends

    Participants attending and completing this programme as a stan-alone certification can choose to enroll for any full advanced diploma.

  • Duration


    30 hours

    1 week (Full-time), or
    5 weeks (Part-time)

    JDMIS runs week-day, weekend and weeknight courses for this popular course. JDMIS also has flexible make-up schedules and graduates can return without cost for refresher courses (subject to availability).

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