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Gain Next-level gem-buying confidence with

Gem & Jewellery Trade Secrets Certificate
Fully Online | 4 weeks | 470 USD
  • Do you fear overpaying for a gem or being cheated with non-genuine synthetics and imitations?
  • Do you feel overwhelmed by the various variations and new types of gems in the market?
  • Unsure of what questions to ask the sellers to determine if a gem is worth paying for? 
gem course screenshots

By the end of this course, you will gain the confidence to

Distinguish and identify different types of gems

Assess more accurately the values of common & less well-known gem types including pearls, jades and diamonds

Know the tell-tale signs and simple tests to tell real gems and pearls from common imitations

Apply best trade practices to get better deals for your next gem & jewellery purchases


Over 7 Exciting & Comprehensive Topics

Assortment of fancy coloured gems and diamonds - cover image for JDMIS Gemmology


Content Duration: 3 hours 15 mins

Picture of fancy looking diamonds - cover image for JDMIS' gemmology lesson


Content Duration: 3 hours 45 mins

Picture of multiple pearl necklaces of different colours laying flat on a white background - JDMIS gemmology cover image


Content Duration: 5 hours

Picture of various types of gemstones with different shapes and colour - Phenomenoal gem cover image


Content Duration: 2 hours 20 mins

Picture of a stunning green colour jade bracelet - gemmology course cover image


Content Duration: 2 hours

Picture of various types of organic gemstones - gemmology course cover image


Content Duration: 3 hours

Picture of all kind of gems of different colours - gemmology course cover image


Content Duration: 2 hours and 10 mins

Expert Instructor

Tanja Sadow

Tanja is an award-winning jewellery designer and gemmologist with more than 4 decades of experience educating the jewellery industry across 4 continents. As Dean and founder of JDMIS, Tanja trains teams from top jewellery brands and works with aspiring artisans to help them achieve brilliance in their careers.

Preview Video

Play Video about Cover image for JDMIS' gemmology course trailer video

Total Value of Over $2,500!

Expert instructor

Learn from Gemmologist & Jewellery Expert, Tanja Sadow with over 4 decades of experience. There will be 3 weekly webinars to review content with the instructor and fellow participants (worth $300)

Professional Certificate

Designed for busy professionals, this intensive course gives you a Certificate of Completion awarded by JDMIS. (worth $300)

Fully Online

24 hours of HD video content with life-time access. (worth $1400) with online quizzes for every topic to ensure you master the materials. (worth $200)

Dedicated Support

Dedicated support via email, webinars and group chat with the expert instructor (worth $300).

Start Date & Early-Bird Offer

Course Price: 470 352 USD! (Limited-time offer)

2024 Quarter 2 enrolment Early-bird cut-off date: 13 May (Mon)

* The schedule for online review webinars is subjected to confirmation after enrolment.

Indicate your interest today and receive one of the limited 15%-OFF vouchers and watch free sample lessons. Only available to the first 25 registrants.

Ready To Enrol? Choose One Of The Options Below:


Module 1 - 90 USD*

This module contains the most essential knowledge for any aspiring gem buyers and jewellery entrepreneur. Master the classification and the key value factors: Cut, Colour, Clarity and Carat Weights. Participants will also attend the first live webinar (see above).

*Fully refundable as course credit if students later enrol for the full GT100 course.

Picture of all digital assets and materials - students get from Gemmology Online by JDMIS

Full GT100 Course - 470 USD

Access all 7 eLearning Modules to go beyond the essential to master pearls, organic gems, jades and a lot more! You will be awarded JDMIS’ Professional Certificate upcon completion.

Best Value!

Picture of Tanja talking at gem jamming class

Physical Course - $1165++

You are welcome to fly in and join us at JDMIS Singapore campus to experience live and hands-on learning with over 1,800 gem samples. To learn more, you may contact


From Over 850 Graduates



Processional Certificate

Upon completing all online modules and passing all assignments, learners will be awarded with an e-Copy of the Professional Certification for Trade Practices 1, which is well recognised by the industry in Singapore and the region.


Tools & Materials

Get ready to embark on an exciting journey with our online course! It’s packed with engaging video content, insightful digital handouts, and interactive exercises. You won’t need any specialised equipment – just bring your passion for learning!

However, for the best experience, we highly recommend getting our Course Kit. As a participant, you can easily purchase this kit online here and we’ll deliver it straight to your doorstep! This ensures you’ll have all the drawing materials you need to excel in your coursework right from the start.

Alternatively, you can buy the tools and materials yourself in your local market! Just visit our Course Kit product page here to know what you’ll need.

GT100 gem course toolkit


2024 Quarter 2 intake’s enrolment cut-off date: 2 May (Thursday). Upon successfully completing all the topics and quizzes, you will receive a Professional Certification in Gems & Jewellery Trade Secrets 100.

The course consists of 24 hours of HD videos and one to two graded assignments for each Module. It usually take up to 5-10 days of intensive learning or longer depending on your self-study pace.

The JDMIS curriculum was designed with input from the jewellery industry, and heeded the call for the programmes to be relevant to today’s
creative world. In Singapore and abroad, organisations such as Tiffany & Co, Cartier, Harry Winston, BP DeSilva Group, Louis Vuitton as well as gemstone manufacturers like Swarovski and Signity value our training curriculum and send their staff for training. International firms such as these and many local jewellery businesses employ JDMIS students in various capacities.The school is registered and recognised as a Private Educational Institution in Singapore, and its courses are recognized by local authorities for employee development within the jewellery industry. JDMIS has established pathways to degree programmes at Birmingham City University and the University of Sunderland. ie: Courses are recognised for academic and vocational study

The course is completely beginner friendly with no special entry requirements except that learners need to have proficient ability in listening and comprehending English as the teaching medium.

The learners from the course will receive access to a series of weekly Q&A webinar where you can get feedback from instructors and engage in discussions with your fellow students. You can also send in your questions via email to the instructor.

Each course has several milestone assignments which you need to complete and submit via the JDMIS Assignment Portal by specified deadlines in order for your instructors to review and provide feedback.

You need to obtain an average mark of 60% or higher to pass the course and receive your Certificate of Completion.

You won’t need any specialised equipment – just bring your passion for learning and any other gems and tools you already have! However, for the best experience, we highly recommend getting our Course Kit. As a participant, you can easily purchase this kit online here and we’ll deliver it straight to your doorstep! 

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