GT100 gemmology course cover

Start your journey at the source of gemmology: learn about gemstone origins, see how gems are mined and how these extraordinarily valuable minerals get to market. Learn about gemmology quality and value factors for all types of gems, from Diamonds to Coloured Stones, Phenomenal gems, Organics to Jade.

This comprehensive course gives you the knowledge and power to take control of your gem purchases (if you are a collector or enthusiast) or your sales process (if you are a designer or jewellery professional). Beyond the common trade practices, you will see and learn about imitations, synthetics and treatments sometimes used to enhance or even to deceive.

Preview video

Course outline

GT101 Coloured Gems - The Earth's Natural Wonders

GT101 Coloured Gems - The Earth's Natural Wonders

Learn about a variety of beautiful natural minerals and how gemmologists classify them. See how easy it is to identify between different gem types. Discover the attributes of gems versus mere minerals and have revealed the difference between fact and the many misconceptions which abound in this field.
GT102 Factors Affecting the Value of Coloured Gems

GT102 Factors Affecting the Value of Coloured Gems

Unlike diamonds, the 4 C's are weighted differently when applied to coloured gems. Learn methods for evaluating colour in gems and discover how clarity types are assessed. See a wide range of cutting styles available in today’s market and start to learn how to make use of practical jewellers tools of the trade.
GT103 Natural Diamonds, Simulants & Synthetics

GT103 Natural Diamonds, Simulants & Synthetics

Many materials are made to resemble diamonds; some can be easily identified, while others nearly identical. The differences between natural and synthetic diamonds are covered. Tips and quick practical tests are shared to assist in identification. A thorough understanding is gained of differences between Diamond Simulants and Synthetic Diamonds.
GT104 Diamonds, the 4 C's & Beyond

GT104 Diamonds, the 4 C's & Beyond

Colour, Clarity, Cut and Carat are explained from a gemmological point of view. The origins and history of diamonds are reviewed, and an understanding of the modern diamond trade is imparted with useful practical buying tips specific to Diamonds revealed.
GT105 Pearls: Natural, Cultured & Imitation

GT105 Pearls: Natural, Cultured & Imitation

Differences between the varieties of pearls readily available in the market today are identified. Origins of some of the most beautiful specimens as well as common imitations and tests are covered. The Pearl culturing process is fully understood. South sea, Japanese and Chinese pearls are closely inspected.
GT106 Assessing Pearl Value

GT106 Assessing Pearl Value

Varied examples are used to identify the different quality factors of pearls and how they affect price. Colour, lustre, shape, spotting, nacre thickness & make are among factors explained & observed. Tips and tricks for buying Pearls are imparted and how to care for these special gems is closely addressed.
GT107 Phenomenal Gemstones

GT107 Phenomenal Gemstones

Discover an array of special gem materials which react in amazing ways to certain light sources to reveal nine types of gem Phenomena. These range from common varieties to the most rare and expensive of collectors’ items. Natural, Synthetic and Imitations are all handled and view closely.
GT108 Jade and Jade Imitations

GT108 Jade and Jade Imitations

As one of the most popular gems in the Far East, Jade has many imitations, and two genuine forms: Jadeite and Nephrite. Learn about Jade's history and lore. Understand the value factors and selection process. Observe and view first-hand the many imitations available on the market today and see some of the difficulties which arise in mining Jade.
GT109 Organic Gems

GT109 Organic Gems

Materials produced by something living or once living are known as Organic Gems. Amber, Jet, Bone, Ivory, Shell and Coral have been found throughout history in jewellery. Discover what has been done and what opportunities abound with these types of gems and with other, less common but unusual, types found in jewellery today.
GT110 Imitations, Synthetics, Assembled gems, Summary, Testing & Next Steps

GT110 Imitations, Synthetics, Assembled gems, Summary, Testing & Next Steps

A useful review is followed by relevant assessments to ensure all salient points have been understood. Final viewing of Imitations, Synthetics and Assembled gems. Next steps are discussed highlighting the importance and methods of testing with the appropriate testing equipment and techniques.

Sample lesson:

Student reviews

  • Diamond - Pyramid Shape

    It was a wonderful course and I have learned a lot, this is definitely a good start to the world of gemology. My family members are avid gem collectors and the knowledge I gained would come in handy during our gem hunt.

    - Ee K. (Singapore)


  • Diamond - Pyramid Shape

    This will be useful for my e-commerce store.

    - Fannie T. (Singapore)


  • Diamond - Pyramid Shape

    I only wish we had more time to look, see and feel more samples of the gems. Otherwise I thoroughly enjoyed myself. It gives me an impetus to learn more about this industry and what it has to offer.

    - Claudia G. (Singapore)


  • Diamond - Pyramid Shape

    Highly recommended! It's good to have time set aside in the week to properly digest the videos. It contains the broadest scope of coverage - appropriate given the current consumer interest.

    - Joanne O. (Singapore)


  • Diamond - Pyramid Shape

    I definitely like this training with good and useful knowledge learnt. It will be good if we have more time to practice during the class... Thank you very much for the training and SkillFuture claimable is also an helpful factor. Thank you.

    - Emily P. (Singapore)


  • Diamond - Pyramid Shape

    As a gem dealer, this (course) was brilliant.

    - Mohamed N. (Singapore)


  • Diamond - Pyramid Shape

    JDMIS is truly awesome. Worth any time and money you invested in. Regardless of whether you are in the jewellery trade or not this is good knowledge.

    - Imran A. (Singapore)


  • Diamond - Pyramid Shape

    I love the way Tanja teach! The class were never bored as she fills the lessons with examples and stories related to the topic of the lessons.

    - Louis L.(Singapore)


  • Diamond - Pyramid Shape

    Love the history, story and trade sharing by Tanja... Very insightful learning!

    - Eileen L. (Singapore)


  • Diamond - Pyramid Shape

    Loving the gem course and Tanja is always very informative... It's engaging and full of new information

    - Faizal S. (Singapore)


  • Diamond - Pyramid Shape

    The curriculum is more than what I expected. I felt engaged throughout the 5 days of lessons. Tanja brought so much industry experience to share. I would recommend this course to all gemstone lovers and those who appreciate the beauty of nature.

    - Eva W. (Singapore)


  • Diamond - Pyramid Shape

    Tanja is amazing, professional and really experiece and patient with all of us.

    - Scott P. (Singapore)


  • Diamond - Pyramid Shape

    Great instructor, great course materials and fun environment... I really learn a lot from this course and really love it. I can identify my gemstones better.

    - Su Myat T.


  • Diamond - Pyramid Shape

    Overall, the course was very well planned, course materials were excellent and the instructor was marvellous. I cannot think of a single complaint and I would highly recommend this course to friends who would be interested to know more about the Jewellery and Gem trade. Keep up the good work!

    - Raymond K.


  • Diamond - Pyramid Shape

    Lovely environment, super stimulation course content, fantastic and really experienced lecturer, absolutely loved the whole course.

    - Claren C. (Singapore)


  • Diamond - Pyramid Shape

    Tanja is exceptional in her lectures. She is very well equipped in both industry experience and theoretical applications which help in further understanding the course material. Tanja's strong passion is evident in her delivery of the course materials to the students, and has made the course extremely enjoyable.

    - Shaun F. (Singapore)


  • Diamond - Pyramid Shape

    Everything the trainer has done for the course is superb. Miss Tanja is a very knowledgeable trainer. Learned so much from her in this course. Thank you.

    - Anthony A. (Singapore)


  • Diamond - Pyramid Shape

    It's always a pleasure to have Tanja teach a class as she is an encyclopedia of knowledge... I will use what I have learned in my own jewellery designs and gemmological knowledge.

    - Margaret P. (Singapore)


  • Diamond - Pyramid Shape

    In a short but intense period, I felt that I learnt a lot of tips that would help me with sourcing for gems, especially tell tale signs of imitations.

    - Geraldine H. (Singapore)


Instructor's profile

  • Tanja, jewellery instructor special portrait

    Tanja Sadow

    Tanja is an award winning jewellery designer & gemmologist 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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Duration & Training Modes

Duration & Training Mode

Duration: 3-5 weeks

Mode: Blended or e-Learning

All important theory and practical demonstrationst will now be delivered through asynchronous (self-paced) online learning. This means that students go through most of the learning at their own pace and convenience via a comprehensive series of online videos and attend live interaction sessions (physical or online) afterwards to receive maximum support and guidance under expert instructors to reinforce the learning of key skills and concepts. For more information on different training modes, click here .

JDMIS also has flexible make-up schedules and graduates can return for free for refresher courses (subjected to availability).

  • Learning path

    Learning path

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

    Next Step: GT200 - Jewellery Trade Practices 2: Gem Identification Methods.

    Next Step (Complementary Jeweller's Knowledge):
    FT100 - Jewellery Fashion Trends 1: Epic and Contemporary Trends.

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

  • Facilities


    The live classes (of the Blending Learning mode) take place in our Gem Vault where participants are able to see, examine, scope and understand Tanja's collection of over 1,800 gems, jewellery pieces and examples, including rare and valuable specimens as well as common imitations found in jewellery markets in the region.

  • Tools & Materials

    Tools & Materials

    Blended-learning students will receive everything they need to complete all their coursework. The course fee includes all the tools, drawing materials and reference materials required for students to complete their coursework efficiently.

    e-Learning students may opt to purchase the standard JDMIS toolkit from us or procure the necessary items themselves.

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Course Fee:

With SkillsFuture Funding up to 70%!

Use our easy calculator below to estimate your payable for each training type after using any government funding and SkillsFuture Credits:

What is the method of training you would like to price?
Find out more about the different methods of training at JDMIS here:

What is your residence status in Singapore?

Will your employer be sponsoring your training?

Estimated Fee Payable
Singaporeans and PRs are eligible for up-to-70% funding for tuition fees. This is an estimate of total course fees payable after SkillsFuture Funding. It is based on the accuracy of information you provided. All grants/SFC payments are subject to SSG approval.

Price represents total course fee payable and is inclusive of tuition, course materials, and GST. SFC claims must be made to SSG 3 days in advance of course start date.

JDMS accepts all major payment methods for payment of jewellery coursesJDMIS accepts Grab Paylater, Atome, and Shopback PaylaterJDMIS accepts all major payment methods, including multiple installment plan services that will allow you to spread your payments in multiple interest-free installments.

Course Gallery

GT100 Gallery Apr21 2
GT100 Gallery Apr21 3
GT100 Gallery Apr21 4
Gem collection 1
Gem collection 2
Gt100 Slider Equipment
Gt100 Gem Students
Gt100 Gem Student Loop
Gemmology course tools and materials kit

Frequently asked questions

  • What is the difference between Blended Learning and e-Learning Modes of Study +

    The Blended Learning is a new option where less physical attendance is required to complete the course. The majority of your learning will take place through structured asynchronous (self-study) learning on our online platform. Once you have completed the required online lessons, you will attend scheduled classroom sessions at JDMIS’ campus (in Singapore) where core techniques and knowledge are reinforced under the guidance of our expert instructors.

    Similar to the Blended Learning, participants of the e-Learning Course will go through self-directed and self-paced learning through our structured online course. After completing the required self-study, participants will attend scheduled live online sessions with an expert instructor and a small group of other online learners.

    In general, the total duration of e-Learning courses is slightly shorter than their blended-learning counterparts due to the absence of physical class attendance. This makes the e-learning courses more affordable, and also a suitable choice for individuals who do not have the option of joining us at the JDMIS Singapore campus.

    For more detailed explanation on the Blended Learning and e-Learning, please visit our Training Mode explainer page.

  • How will the schedules work? +

    Most of your jewellery training will be delivered through HD-quality recordings that you can view at your own pace and convenience. Live session with the instructor (physical for Blended, and online for eLearning) will be scheduled in between or near the end of the course to reinforce your mastery of key concepts.

  • What if I have questions during self-study? +

    The learners from each course will receive access to an exclusive WhatsApp Group where you can get feedback from instructors and engage in discussions with your fellow students. You can also raise your questions during the live lessons with the instructors.

  • How much time do I need to study a week? +

    As most of the course is self-paced, you conduct your study at your own pace that suits your learning style. but the general recommended duration is 1-2 days a week.
  • Are the tools & materials included? If not, how much do I need to pay? +

    The cost of tools and materials is already included in the course fee. All students will receive the same tool kit that they will need to complete their course efficiently. For Singaporean and PRs, the amount will be invoiced and paid separately because tools & materials fees are not covered by SSG funding. Overseas students doing the online only/e-Learning option are eligible to opt out of purchasing the toolkit by letting our registrar know at the time of your registration.

  • How will my assignment be graded and what do I need to pass? +

    You are responsible for completing the online lessons before attending the live sessions with JDMIS instructors. Each course has several milestone assignments which you need to complete and submit by specified deadlines in order for your instructors to review and provide feedback.

    In order for your instructors to review your assignments and provide feedback, you need to take photos/scans of your completed work (design or jewellery piece) and submit them onto the JDMIS online assessment portal.

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

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