CDG Cheat Sheet 2026

The 30 highest-yield CDG facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which risk is most critical when grading a diamond submitted alongside a GIA grading report? → Assuming the report is authentic without verification
2. How should an CDG professional handle unexpected results that differ from predictions? → Analyze factors, document findings, and adjust the approach based on what was learned
3. Which clarity characteristic type CANNOT be improved through laser drilling? → White feathers or clouds
4. A professional diamond grader should recuse themselves from grading a stone when: → They have a financial interest in the stone's grade outcome
5. Per GIA standards, which measurement sequence is recorded first for a round diamond? → Minimum diameter × maximum diameter × depth
6. How should an CDG professional present complex findings to non-experts? → Translate into accessible language, use visuals, and verify understanding
7. Which of the following is NOT typically included in a professional diamond grading report? → Retail market value
8. Why is polishing important after cutting? → It enhances sparkle
9. Which security measure most effectively reduces the risk of internal theft of high-value diamonds in a grading laboratory? → Requiring dual control—two-person verification for high-value stones
10. What is a common shape for polished diamonds? → Round brilliant
11. What risk is associated with exposing a fracture-filled diamond to the intense heat of jewelry repair? → Melting or vaporization of the glass filler, destroying the clarity enhancement
12. How should CDG professionals stay current with regulatory changes? → Actively monitor updates through professional associations and continuing education
13. How should an CDG professional approach a novel situation not covered by standard procedures? → Apply foundational principles, assess risks, consult resources, and document decisions
14. What is the purpose of laser drilling in diamond treatment? → To reach dark inclusions and remove or bleach them
15. Which grading report is widely accepted for diamond certification? → GIA report
16. Which mineral is the hardest known natural material? → Diamond
17. What causes Type IIb diamonds to be electrically semi-conductive? → Boron substituting for carbon in the lattice
18. What risk is introduced when a diamond has been surface-coated to artificially improve its apparent color grade? → The coating may be mistaken for natural color, causing significant over-valuation
19. What legal risk does selling a fracture-filled diamond without disclosing the treatment create? → Potential fraud or misrepresentation liability under consumer protection law
20. How long should a professional diamond grading laboratory typically retain grading records in the US? → At minimum 7 years, in line with standard business record-keeping practices
21. You observe an indented natural at the girdle of a diamond during clarity grading. How is this characteristic correctly classified? → As an internal characteristic because it dips below the original polished surface
22. A diamond grader identifies a stone as likely laboratory-grown rather than natural. The grader's professional responsibility is to: → Document the observation, conduct confirmatory testing, and disclose on the report
23. How do CDG professionals establish measurable quality objectives? → Defining specific, measurable, achievable, relevant, and time-bound targets
24. What is reflective practice in Certified Diamond Grader professional growth? → Systematically examining experiences to gain insight and improve future practice
25. Which diamond type classification is defined by the absence of both nitrogen and boron impurities? → Type IIa
26. Which organization requires disclosure of fracture filling and will not grade treated diamonds on standard reports? → GIA (Gemological Institute of America)
27. When handling a diamond worth over $100,000 in a professional laboratory, security protocol typically requires: → Enhanced chain of custody documentation and dual verification at each transfer point
28. How do CDG professionals effectively transfer training knowledge to workplace practice? → Through supervised practice, mentoring, and progressive independence with feedback
29. Which of the following is a polymorph of diamond? → Graphite
30. Which of the following best describes the mineral 'moissanite' in relation to diamond? → A diamond simulant composed of silicon carbide (SiC)