CDG Study Guide 2026
Everything you need to pass the CDG exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
CDG exam key facts
📋 CDG Exam Format at a Glance
📚 CDG Topics to Study (34)
✍️ Sample CDG Questions & Answers
1. A diamond tests positive on a standard thermal conductivity tester but displays unusual strain patterns under the microscope. What is the correct risk management response?
Standard testers confirm thermal conductivity but cannot distinguish all synthetics or certain simulants; conflicting evidence requires escalation to definitive spectroscopic analysis.
2. How does KM (Kiduah Meyuchad) drilling differ from traditional laser drilling?
KM drilling creates a surface-reaching fracture that reaches the inclusion without leaving a straight drill hole, making it harder to detect than traditional laser drilling.
3. What substance is most commonly used in fracture filling of diamonds?
Lead glass is the most common fracture-filling material because its refractive index closely matches that of diamond, making the filled fractures nearly invisible.
4. Which method is commonly used for root cause analysis in CDG quality management?
Structured root cause analysis methods like Five Whys and fishbone diagrams systematically trace problems to their fundamental causes rather than symptoms.
5. What is the role of internal audits in Certified Diamond Grader compliance management?
Internal audits proactively verify compliance, identify gaps, and drive improvement before external inspections or incidents reveal problems.
6. The difference between a diamond grading report and a diamond appraisal is best described as:
Grading reports objectively document the 4Cs and other properties, while appraisals assign a monetary value for insurance or resale purposes.
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📖 CDG Guides & Articles
What Practice Test Geeks adds beyond an AI chat for CDG
An AI chatbot can quiz you, but it can't reproduce the exam conditions or keep your record. Here you get:
- A timed, full-length CDG mock exam — 100 questions in 120 minutes with a 75% pass mark, modeled on the official exam's question count and time limit, followed by a score report broken down by exam domain.
- A fixed CDG question bank: the same test every attempt, so your score is comparable from one try to the next instead of changing with every regenerated quiz.
- Progress saved on your device: completed tests, scores and missed questions stay in My Progress, so you can retake only what you got wrong.
- A printable CDG cheat sheet you can print or save as a PDF.
- CDG flashcards built from the same question bank.
- Free CDG practice tests with the correct answer shown after each question.
How this page was made: written with AI tools and published by Nathan Beja, founder of Practice Test Geeks, who is responsible for its content. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy
Sources & references
Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy
- education.hrdantwerp.com — Test delivery, eligibility, fees, exam format, registration deadline, test dates, score validity · verified Oct 2026