Step 1 · record
Build the field card before the shortlist.
- 01Both facesStraight, sharp photographs
- 02EdgePlain, reeded, lettered, cut
- 03DiameterWidest point in millimetres
- 04WeightGrams, without scraping
- 05LettersCopy only what is visible
- 06ContextDepth and private location
A round disc with UNITED STATES OF AMERICA or a denomination may be a U.S. coin. Without those clues, keep tokens, medals, buttons, washers, and foreign coins in the shortlist.
Confirm it with the other face, letters, size, weight, and an official database.Step 2 · measure
Current U.S. coins at true relative size.
The circles are scaled against each other—not against your screen. Compare the printed millimetres with a ruler.
Dime
- Diameter
- 17.91 mm
- Weight
- 2.268 g
- Edge
- Reeded
Smallest current silver-colored coin
Cent
- Diameter
- 19.05 mm
- Weight
- 2.50 g
- Edge
- Plain
Often copper-colored, but not always
Nickel
- Diameter
- 21.21 mm
- Weight
- 5.00 g
- Edge
- Plain
Larger and thicker than a dime
Quarter
- Diameter
- 24.26 mm
- Weight
- 5.67 g
- Edge
- Reeded
Washington or a national program design
Dollar
- Diameter
- 26.49 mm
- Weight
- 8.10 g
- Edge
- Lettered
Usually golden-colored
Half dollar
- Diameter
- 30.61 mm
- Weight
- 11.34 g
- Edge
- Reeded
Much larger than a quarter
Step 3 · match the main design
Move along the portrait timeline.
Cent
- 1859–1909Indian Head
- 1909–1958Lincoln + wheat ears
- 1959–2008Lincoln Memorial
- 2009Four Lincoln life reverses
- 2010 onwardUnion Shield reverse
Nickel
- 1913–1938Native American + bison
- 1938–2003Jefferson + Monticello
- 2004–2005Four Westward Journey reverses
- From 2006Monticello returns
Dime
- 1916–1945Winged Liberty (“Mercury”)
- 1946–2025Franklin D. Roosevelt
- 2026Emerging Liberty
Quarter
- 1892–1916Barber Liberty
- 1916–1930Standing Liberty
- 1932 onwardWashington portrait family
- 1999 onwardMany changing reverse programs
Half dollar
- 1916–1947Walking Liberty
- 1948–1963Benjamin Franklin
- 1964–2025John F. Kennedy
- 2026Enduring Liberty
These are fast orientation bands, not a complete U.S. type catalogue. Confirm the exact year and design on the U.S. Mint denomination page.
Step 4 · date and mint mark
Read the small letter after the big design.
A mint mark is a small letter showing where the coin was made. Modern marks include P, D, S, and W. Historic issues can use marks such as O or CC.
No mint mark often means Philadelphia, but exceptions exist. Always check the exact series and year.
Common lookalikes
A portrait does not automatically mean coin.
Legal context
The United States has no single PAS-style portal.
Rules depend on who manages the land. In national parks, metal detecting, possessing a detector, digging, and removing archaeological objects are prohibited. Leave an object in place and tell a ranger. On other public land, ask the managing agency before detecting or removing anything.
Do not invent a nationwide reporting duty for an ordinary coin lawfully found on private land. The landowner agreement and state or local rules still matter.