GIA Cheat Sheet 2026

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

1. What is the primary purpose of the plotting diagram included on a GIA Diamond Grading Report? → To map the location and nature of clarity characteristics
2. Which proportional element most directly affects a round brilliant diamond's light return or 'brilliance'? → Pavilion angle
3. What is 'scintillation' as defined by GIA in evaluating cut quality? → The pattern of light and dark areas plus the flashes of light when a diamond moves
4. What is the refractive index (RI) range used to distinguish corundum (ruby/sapphire) from other red or blue gemstones? → 1.762–1.770
5. A client requests an appraisal for 'equitable distribution' in a divorce proceeding. Which value basis is most appropriate? → Fair market value
6. GIA's cut grade for standard round brilliant diamonds evaluates which combination of factors? → Brightness, fire, and scintillation
7. Which of the following is an amorphous gemstone, meaning it lacks a regular crystalline structure? → Opal
8. Which precious metal alloy is most commonly used in high-end diamond engagement rings due to its white color, durability, and hypoallergenic properties? → Palladium or platinum
9. Which term describes the practice of mixing certified conflict-free rough diamonds with undocumented stones before sale to obscure the true origin? → Commingling
10. The De Beers Tracr platform uses which technology to record the chain of custody for individual diamonds? → Blockchain distributed ledger technology
11. What does 'fluorescence' mean in the context of GIA diamond grading? → The diamond's visible glow under UV light
12. Which tool is primarily used for grading a diamond’s clarity? → 10x loupe
13. The GIA Colorimeter measures diamond color by comparing it against which standard? → Master comparison stones
14. Fancy vivid yellow diamonds command higher prices than fancy light yellow diamonds primarily because: → Stronger color saturation is rarer and more desirable, commanding a significant premium
15. What does the term 'fluorescence' describe in diamond grading? → A diamond's reaction to ultraviolet light
16. What is the purpose of fracture filling in diamonds? → Fill cracks to enhance clarity
17. Which optical phenomenon causes a six-rayed star to appear on the surface of a star sapphire? → Asterism
18. What does FTIR spectroscopy primarily measure in diamond samples? → Absorption of infrared radiation
19. In the context of diamond market economics, what is 'price maintenance' historically associated with De Beers? → Stockpiling excess rough supply to prevent price drops during downturns
20. A 'cloud' inclusion in a diamond is best described as: → A hazy area caused by a cluster of many tiny pinpoints or crystals
21. A diamond with a depth percentage of 62% and a table percentage of 57% would most likely receive which GIA cut grade? → Excellent
22. An appraiser discovers that a diamond has been laser-drilled and fracture-filled. How should this affect the appraisal? → The value should be adjusted downward and the treatment disclosed prominently
23. When a diamond's fluorescence is described as 'very strong blue,' how does this typically affect its value for a D-color stone? → It slightly decreases value due to potential haziness and buyer wariness
24. The 'pipeline' in the diamond industry refers to: → The chain from rough mining through cutting, polishing, and retail sale
25. The 'Rapaport Price List' is primarily used in the diamond industry as: → A wholesale benchmark for polished diamonds
26. Which C would most likely affect a diamond’s transparency? → Clarity
27. What role does documentation play in Certified Diamonds Gemological Institute of America professional practice? → It creates accountability, supports decision-making, and provides legal protection
28. Which of the following best describes the ethical obligation of a GIA-trained salesperson regarding diamond treatments? → Disclose all known treatments proactively, regardless of whether the customer asks
29. What characteristic fluorescence pattern does a CVD synthetic diamond typically show under the DiamondView? → Layered or striated parallel growth lines
30. When a GIA report lists a diamond as 'Internally Flawless (IF),' the appraiser should consider that: → The stone has no internal characteristics but may have minor surface blemishes