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Professional Certificate

Gem & Jewellery Trade Secrets
Fully Online | 2-4 weeks | 480 360 USD

Do you lack the confidence in your gem & jewellery purchases?

  • Do you fear overpaying for a gem or being cheated with non-genuine synthetics and imitations?
  • Or feel confused by the price differences between similar-looking gemstones?
  • 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? 

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

gem course screenshots

Practical & Convenient

Expert instructor

Learn from Gemmologist & Jewellery Expert, Tanja Sadow, who has over 4 decades of experience.


Designed for busy professionals, this course gives you certified gemmological knowledge in just 2-4 weeks.

Fully Online

All important theory and practical demonstrations are covered with detailed, closeup micro-learning, in total of over 22 hours worth of HD-quality content.

Dedicated Support

In addition to grading by the instructors, students will also be supported with several once-a-week live webinars and a dedicated Facebook group.


Over 8 Comprehensive Topics

Classifications and Attributes of Gems

Pearl values and Classifications

the Value Factors of Coloured Gems

Organic Gemstones

Identify Natural Diamonds, Simulants & Synthetics

Phenomenal gemstones

The Value Factors of Diamonds (4 Cs)

Jade history & Imitations

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

In 2-4 weeks, obtain

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.

Do you need the

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

Early Bird Promotion

25% OFF

- Life-time access to 7 On-Demand eLearning Modules ($700)
- Access to 4 weekly Q&A live webinars with the expert instructor ($400)
- Dedicated Facebook-group and email support ($300)
- JDMIS Professional Certificate (soft copy) upon satisfactory completion ($200)

Total value: 1,600 USD

Now Only 360 USD For A Limited Time!

Course Starts In

picture of an assortment of gems of different colours

Module 1 - 100 USD

Start with the first and most fundamental module on the classifications and value factors of coloured gems.
*Fully refundable as course credit if students later enrol for the full GT100 course.


GT100 Online - 700 360 USD

Take all 7 eLearning Modules to master 10 gemmology topics, supported with weekly live webinars and Facebook Group. Awarded JDMIS Certificate upon completion.

Picture of Tanja talking at gem jamming class

Physical Course - 1165++ USD

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.

Some Of The Reviews

From Over 850 GT100 Graduates



Tanja and gemmology graduates

Founded in 2007, the Jewellery Design and Management International School (JDMIS) is a unique school in Asia providing Jewellery Design and Management Programs. JDMIS is Singapore’s only specialized jewellery school and offers end-to-end jewellery education, which includes Professional Certificate Courses leading to Diploma and Advanced Diploma. 

15 Years of Operation

20K Participants

5,500 Certified graduates

30+ Programmes

Be confident in your next gem & jewellery purchase

Limited-time Launch Offer
25% OFF | 30-day Satisfaction Guaranteed


Most frequent questions and answers

The course has over 22 hours worth of HD recording plus assignments and quizes. It will take 5-7 days of full-time study or 2-4 weeks part-time.

The course has an open enrolment policy but you are encouraged to join by 11 October 2023 (Wed) to enjoy all the weekly live Q&A webinars and early-bird discount. Upon successfully completing all the topics and assignments (graded with detailed feedback by the instructor), you will be awarded a Professional e-Certificate

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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111 Middle Road #01-03/04 National Design Centre Singapore 188969
Email us: [email protected]