NGC Error Coins & Mint Varieties 2 — Questions and Answers
Question 1: What causes a 'clipped planchet' error?
- A planchet trimmed by the mint during final quality inspection
- An edge-lettering malfunction during the production process
- A malfunction in the blanking press that removes a portion of the planchet before it is struck (Correct answer)
- Damage to the coin's edge sustained after years of circulation
Correct answer: A malfunction in the blanking press that removes a portion of the planchet before it is struck
Clipped planchet errors result from a malfunction in the blanking press where the strip of metal overlaps a previously punched hole, causing a curved or straight section to be missing from the planchet.
Question 2: The Sheldon variety numbering system was originally created to catalog which series of U.S. coins?
- Morgan Silver Dollars
- Large Cents (Correct answer)
- Trade Dollars
- Draped Bust coinage across all denominations
Correct answer: Large Cents
Dr. William Sheldon created his variety numbering system in 1949 specifically for Early American Large Cents, cataloging distinct die marriages that are still referenced as Sheldon numbers today.
Question 3: In numismatics, 'VAM' varieties specifically catalog die varieties for which coinage?
- A grading methodology applied to all U.S. commemorative coins
- A value assessment metric used for evaluating key-date coins
- A visual appearance measurement system used by third-party grading services
- Die varieties for Morgan and Peace dollars, named after researchers Van Allen and Mallis (Correct answer)
Correct answer: Die varieties for Morgan and Peace dollars, named after researchers Van Allen and Mallis
VAM stands for Van Allen-Mallis, honoring Leroy Van Allen and A. George Mallis who authored the definitive reference cataloging hundreds of Morgan and Peace dollar die varieties.
Question 4: A 'lamination' error on a coin is caused by:
- An improper protective coating applied to the coin after minting
- Two planchets accidentally bonded together during the rolling process
- Impurities or defects in the planchet metal that cause surface layers to separate (Correct answer)
- Insufficient striking pressure leaving design elements weak and peeling
Correct answer: Impurities or defects in the planchet metal that cause surface layers to separate
Lamination errors result from internal impurities, inclusions, or rolling defects in the planchet that cause a thin layer of metal to flake, peel, or separate from the coin's surface.
Question 5: What is the key distinction between a 'mechanical doubled die' and a 'hub doubled die'?
- Hub doubling occurs during die creation while mechanical doubling results from die bounce or shift during the actual strike (Correct answer)
- Mechanical doubling is more valuable to collectors than hub doubling
- Hub doubling appears only on the date while mechanical doubling affects the entire design equally
- Mechanical doubling occurs exclusively on proof coins struck at the San Francisco Mint
Correct answer: Hub doubling occurs during die creation while mechanical doubling results from die bounce or shift during the actual strike
Hub doubling is a true variety created when the die receives a doubled impression during hubbing, while mechanical doubling (also called machine doubling or strike doubling) is a worthless strike artifact caused by die movement or bounce during the coin-striking process.
Question 6: A 'brockage' error coin is created when:
- A planchet receives multiple off-center strikes in the same production run
- A coin becomes so distorted it wraps around the die after repeated strikes
- A previously struck coin remains in the coining chamber and impresses a mirror image of its design onto the next planchet (Correct answer)
- Two planchets are accidentally fed into the coining chamber simultaneously
Correct answer: A previously struck coin remains in the coining chamber and impresses a mirror image of its design onto the next planchet
A brockage occurs when a struck coin adheres to the die face and acts as a makeshift die for the next planchet, impressing an incuse mirror image of one side onto the new coin.
Question 7: What is a 'split planchet' error?
- A planchet intentionally cut in half by the mint for metallurgical quality testing
- A planchet with a crack running from the edge toward the center
- A planchet composed of two different metal layers laminated together intentionally
- A planchet that separated into two thin layers, either before or after being struck (Correct answer)
Correct answer: A planchet that separated into two thin layers, either before or after being struck
A split planchet error results from severe lamination defects that cause the planchet to fully split into two distinct thin pieces, sometimes producing a coin struck on one of the resulting thin halves.
NGC Error Coins & Mint Varieties 2
What causes a 'clipped planchet' error?