NGC Authentication Techniques & Tools 2

Question 1

Which tool is most commonly used to measure the specific gravity of a coin to detect base metal forgeries?

Accepted Answer

Hydrostatic scale

Answer

A hydrostatic scale measures specific gravity by comparing a coin's weight in air versus water, revealing whether the alloy composition matches genuine coins.

Question 2

When examining a coin under a microscope for die characteristics, what does 'die polish' typically appear as?

Accepted Answer

Fine parallel lines in the coin's fields from polishing the die

Answer

Die polish lines are fine parallel lines visible in a coin's fields that result from the mint polishing the die surface, not the coin itself.

Question 3

What is the primary purpose of X-ray fluorescence (XRF) analysis in coin authentication?

Accepted Answer

To determine the elemental composition of the coin's metal

Answer

XRF analysis bombards a coin with X-rays and measures the resulting fluorescence to identify the elemental composition of the metal non-destructively.

Question 4

A coin exhibits mushy, indistinct lettering in the legend but sharp design elements in the center. This pattern is most consistent with:

Accepted Answer

A cast counterfeit where the mold captured detail unevenly

Answer

Cast counterfeits often show uneven detail reproduction because the casting process captures fine lettering at the edges less precisely than central design elements.

Question 5

Which characteristic best differentiates a 'whizzed' coin from a genuinely uncirculated example?

Accepted Answer

Whizzed coins show artificial luster with a grainy, directional texture under magnification

Answer

Whizzing involves mechanically buffing a coin's surface, producing an artificial sheen with a distinctive grainy or directional texture visible under magnification unlike genuine mint luster.

(NGC) Numismatic Guaranty Corporation Certified Professional Practice Test

(NGC) Numismatic Guaranty Corporation Certified Professional Practice Test

NGC Authentication Techniques & Tools 2