NGC Cheat Sheet 2026

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

1. The Umayyad caliphate introduced purely epigraphic (text-only) Islamic gold dinars in 696-697 AD under which caliph? → Abd al-Malik
2. Which Roman emperor first introduced the solidus as a standardized gold coin? → Constantine I
3. Which of the following best describes 'assay certification' on a precious metal bar? → An official confirmation of the metal's purity and weight by an independent assayer
4. In the context of NGC certification, what is the most important consideration when implementing collection management & storage? → Ensuring alignment with established standards, stakeholder needs, and best practices
5. A coin dealer sees a bar stamped '.9167 Au.' What karat gold does this represent? → 22 karat
6. Which of the following correctly describes 'original skin' on a coin? → The undisturbed original surface patina and luster as it left the mint
7. Which coin storage product should be AVOIDED for long-term storage due to chemical reactivity with copper alloy coins? → Vinyl (PVC) soft flip holders
8. A 'cob' coin (macuquina) produced in Spanish colonial mints during the medieval/early modern period is best described as what? → A rough, irregularly shaped piece cut from a silver bar and struck
9. What does the 'S' mint mark on a modern U.S. proof coin indicate in NGC's classification system? → Struck at the San Francisco Mint
10. The London Bullion Market Association (LBMA) Good Delivery standard for silver bars requires a minimum fineness of: → .999
11. A soiled banknote with heavy folds, tears, and missing pieces but still complete enough to identify its design is typically graded in which range? → About Good (AG) to Good (G)
12. What is the main purpose of authentication in numismatics? → Verify legitimacy
13. What does the term 'electrum' refer to in the context of precious metals history? → A naturally occurring alloy of gold and silver
14. What does the term 'bid increment' mean in the context of a live numismatic auction? → The minimum amount by which each successive bid must exceed the previous one
15. What numismatic term describes the practice of replacing a lower-grade coin in a collection with a higher-grade example of the same date and mint? → Upgrading
16. What does the term 'buyer's premium' refer to in a numismatic auction? → A fee added to the hammer price paid by the winning bidder
17. What NGC classification applies to a state quarter found in circulation that shows no signs of wear? → Mint State (MS)
18. In NGC's classification, an 'Enhanced Uncirculated' coin typically features which surface characteristic? → Multiple finish types on different design elements
19. Which of the following is the safest long-term storage medium for paper currency and banknotes? → Archival polyester (Mylar) currency sleeves
20. A numismatist finds that a suspected gold coin produces a dull 'thud' rather than a clear ring when tapped and allowed to vibrate freely. This indicates: → The coin may be plated, cast, or made of a non-precious metal alloy
21. How can feedback improve service? → Improve service
22. Which US banknote type issued between 1878 and 1923 was redeemable directly for silver dollars held on deposit at the US Treasury? → Silver Certificates
23. What storage advantage does an NGC multi-coin holder (also called a 'multi-coin slab' or set box) provide over individual slabs? → It keeps thematically or series-related coins together in a single certified unit
24. What is 'vermeil' in terms of precious metal standards? → Gold-plated sterling silver meeting a minimum thickness standard
25. In the context of NGC certification, what is the most important consideration when implementing auction practices & market trends? → Ensuring alignment with established standards, stakeholder needs, and best practices
26. A numismatist cataloging a collection for estate planning should include which of the following for each significant coin? → NGC or PCGS certification number, grade, and recent comparable auction results
27. How does NGC differentiate a 'clad' coin from a 'silver' coin in its modern classification labels for Washington quarters? → By noting the metal composition in the label, such as 'Silver' for 90% silver issues
28. Which medieval coin type, first struck in Florence in 1252, became a pan-European gold standard for trade? → The florin
29. Which modern U.S. Mint product is classified by NGC as 'SP' (Specimen)? → West Point Mint bullion coins with special finishes
30. What material is used to make NGC's tamper-evident coin holders (slabs)? → Polycarbonate plastic