NGC Counterfeit Detection Methods 2 — Questions and Answers
Question 1: Which diagnostic tool uses magnetic properties to help distinguish genuine U.S. coins from counterfeits?
- Sigma Metalytics Precious Metal Verifier (Correct answer)
- Fisch gauge
- Sheldon scale
- Photograde system
Correct answer: Sigma Metalytics Precious Metal Verifier
The Sigma Metalytics Precious Metal Verifier uses electromagnetic properties to verify metal composition without damaging the coin.
Question 2: On a genuine Morgan Silver Dollar, the eagle's breast feathers should display what characteristic under magnification?
- Smooth, flat surfaces with no texture
- Clearly defined individual feathers with crisp detail (Correct answer)
- Granular, sandblasted appearance
- Overlapping scales like fish skin
Correct answer: Clearly defined individual feathers with crisp detail
Genuine Morgan dollars show crisp, individually defined breast feathers that are a hallmark of authentic die work.
Question 3: What is a 'spark test' used to detect when authenticating coins?
- A laser diffraction method for surface analysis
- Striking a coin against a steel rod to check the ring
- Applying electric current to detect plating (Correct answer)
- Using UV light to check fluorescent inclusions
Correct answer: Applying electric current to detect plating
Applying low electric current can reveal plated coins since the base metal beneath a plating layer conducts differently.
Question 4: Die-struck counterfeits are generally considered more dangerous than cast fakes because they:
- Always use genuine silver content
- Reproduce sharper detail and correct surface texture (Correct answer)
- Are made by government mints abroad
- Pass all XRF spectroscopy tests
Correct answer: Reproduce sharper detail and correct surface texture
Die-struck counterfeits are pressed with hardened dies, reproducing much sharper detail and more authentic-looking surfaces than cast fakes.
Question 5: When examining a suspected counterfeit Trade Dollar, which area is MOST commonly found to show weakness or incorrect lettering?
- The date numerals
- Stars on the obverse
- The motto 'E PLURIBUS UNUM' (Correct answer)
- Edge reeding
Correct answer: The motto 'E PLURIBUS UNUM'
Counterfeiters often struggle to perfectly replicate fine motto lettering, and 'E PLURIBUS UNUM' on Trade Dollars is a frequent weak point.
Question 6: What does 'ghosting' on a coin indicate in the context of counterfeit detection?
- Correct die flow lines indicating authenticity
- A raised image from the opposite side visible on a struck coin
- UV-reactive residue from cleaning
- Tooling marks from manual engraving on fakes (Correct answer)
Correct answer: Tooling marks from manual engraving on fakes
In counterfeit detection, tooling marks (sometimes called ghosting marks) are signs that a faker manually touched up or enhanced details on the coin.
Question 7: The specific gravity test for silver coins relies on which physical principle?
- Silver's unique magnetic susceptibility
- Archimedes' principle of water displacement (Correct answer)
- Silver's fluorescence under UV light
- Silver's melting point difference from base metals
Correct answer: Archimedes' principle of water displacement
Specific gravity testing uses Archimedes' principle — the coin is weighed in air and in water to calculate density, which reveals metal composition.
NGC Counterfeit Detection Methods 2
Which diagnostic tool uses magnetic properties to help distinguish genuine U.S. coins from counterfeits?