CGA Cheat Sheet 2026

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

1. The 'scope of work' in an appraisal refers to: → The type and extent of research and analysis applied to complete the assignment
2. What is 'aqua regia' and why is it significant to precious metal testing? → A mixture of nitric and hydrochloric acids that dissolves gold and platinum
3. A gemologist uses a spectroscope to identify a gemstone. What does this instrument measure? → Absorption of light wavelengths
4. Which precious metal is most commonly alloyed with gold to create white gold? → Nickel or palladium
5. What is the ethical significance of maintaining a separation between an appraiser's role as a buyer/seller and their role as an appraiser? → It prevents conflicts of interest that could compromise the objectivity of valuations
6. When writing a jewelry appraisal report, the description of a diamond should include which of the following groups of characteristics? → Color, clarity, carat weight, and cut grade
7. An oil-filled emerald requires special care instructions for the buyer primarily because: → Ultrasonic cleaners, steamers, and solvents can remove or damage the filler
8. Which gemstone treatment is most effectively detected by observing 'snow-globe' effect inclusions or feathers that reach the surface under magnification? → Fracture filling with glass or resin
9. Gold's resistance to corrosion and tarnish is primarily due to its: → High ionization energy and chemical nobility
10. Which diamond cutting style maximizes fire and brilliance through triangular and kite-shaped facets? → Brilliant cut
11. Which optical phenomenon causes a star sapphire to display a six-rayed star when viewed under a single light source? → Asterism
12. Which factor MOST significantly affects the quality of technical outcomes in CGA practice? → The practitioner's training, preparation, and attention to detail
13. Tanzanite is almost universally heat-treated before sale. What color change does this treatment produce? → Brown to blue-violet
14. What should a complete appraisal report include? → All relevant details, methodology, and purpose of appraisal
15. What is 'brilliance' in a diamond? → The total reflection of white light from within and surface of a diamond
16. A CGA receives a contingency fee offer where payment depends on achieving a minimum appraised value. What should the appraiser do? → Decline, as contingency fees based on appraised value are ethically prohibited
17. Which foundational principle is MOST important for success in Certified Gemologist Appraiser? → Commitment to continuous learning, ethical practice, and quality outcomes
18. A gemologist measures a stone's refractive index at 1.76 on a standard refractometer. Which gemstone does this value most closely match? → Ruby/Corundum (1.76–1.77)
19. A CGA appraiser who knowingly fails to disclose a significant gemstone treatment in a written appraisal report is most directly in violation of: → USPAP standards and professional ethics requirements
20. What is the primary purpose of an appraisal report? → To communicate the item’s value and the rationale for it
21. When appraising an estate piece for fair market value, the appraiser should consider: → What a willing buyer would pay a willing seller with neither under compulsion
22. In Certified Gemologist Appraiser practice, what is the CORRECT sequence when performing a technical procedure? → Plan, prepare, execute, verify, and document
23. Which color is considered the most valuable for a ruby? → Vivid red ('pigeon's blood')
24. Which organization publishes internationally recognized disclosure guidelines for gemstone treatments used by the trade? → CIBJO (World Jewellery Confederation)
25. Which of the following scenarios most likely constitutes insurance fraud involving a gemstone appraiser? → Knowingly overstating a gem's value to help a client collect a higher insurance payout
26. Which term refers to a gemstone’s resistance to scratching? → Hardness
27. Which type of pearl is most valuable and commands the highest prices in the US market? → South Sea pearls
28. An appraiser is asked for a 'fair market value' of a gold ingot. Which scenario best defines this value? → The price a willing buyer and seller agree upon, both informed and unpressured
29. An appraiser is asked to provide a 'verbal appraisal.' Under USPAP, which statement is TRUE? → Verbal appraisals are acceptable but still require a work file
30. What distinguishes a 'Type IIa' diamond from a 'Type Ia' diamond in terms of chemical composition? → Type IIa contains virtually no nitrogen; Type Ia contains nitrogen aggregates