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.
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Course outline
GT101 Coloured Gems - The Earth's Natural Wonders
GT102 Factors Affecting the Value of Coloured Gems
GT103 Natural Diamonds, Simulants & Synthetics
GT104 Diamonds, the 4 C's & Beyond
GT105 Pearls: Natural, Cultured & Imitation
GT106 Assessing Pearl Value
GT107 Phenomenal Gemstones
GT108 Jade and Jade Imitations
GT109 Organic Gems
GT110 Imitations, Synthetics, Assembled gems, Summary, Testing & Next Steps
Sample lesson:
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Instructor's profile
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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: 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).
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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.
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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.
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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 Gallery
Frequently asked questions
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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.
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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.
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What if I have questions during self-study? +
The learners from each course will receive access to an exclusive Facebook 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.
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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.If you are doing the online only/e-Learning option, you may choose to opt out of purchasing the toolkit by letting our registrar know at the time of your registration. For more details on what is in the tool kit, please click here.
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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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