Six tests you can do with a kitchen scale, calipers, a strong magnet, and the published mint specs of the coin you're looking at. Most counterfeits fail at least one test; the good ones fail several.
No single test is conclusive on its own. Run two or three before trusting a coin worth more than a few dollars. Stack the cheap, fast tests (weight, magnet, dimensions) first; reserve the slower ones (ping, specific gravity) for when something on the first round is off.
Morgan dollar — mint spec 26.73 g
1 Weight
Difficulty: easy · Tools: kitchen scale (0.01 g resolution)
Every authentic coin has a published mint weight. A real 1964 Roosevelt dime weighs 2.50 g. A real Mercury dime weighs 2.50 g. A real Morgan dollar weighs 26.73 g. Worn circulated coins lose mass over a century — usually 1–3% — but never gain it.
If you put a coin on a scale and the reading is more than ~3% below mint spec or anything above spec, treat it as a strong fake signal. Counterfeit silver-plated tungsten or copper-cored fakes often miss spec by 5%+ because they had to compromise to match dimensions.
Mint weights for common silver coinage
Coin
Spec (g)
Tolerance
Mercury / Roosevelt Dime (silver)
2.50
2.43–2.50
Washington / Standing Liberty Quarter
6.25
6.06–6.25
Walking Liberty / Franklin / 1964 Kennedy Half
12.50
12.13–12.50
Morgan / Peace Dollar
26.73
25.93–26.73
Trade Dollar (US)
27.22
26.40–27.22
1840s sterling shilling (UK)
5.66
5.49–5.66
Half Crown (UK)
14.14
13.72–14.14
Crown (UK)
28.28
27.43–28.28
Voyageur Silver Dollar (Canada)
23.33
22.63–23.33
8 reales / Caballito peso
27.07
26.26–27.07
Watch out for
Counterfeits that match weight by using a copper or tungsten core with a thin silver outer layer. They pass weight, fail specific gravity. See test #5.
Walking Liberty half — 30.61 mm × 2.15 mm
2 Dimensions
Difficulty: easy · Tools: digital calipers ($10–15 set)
Every coin has a defined diameter and edge thickness. Counterfeits often hit weight specs by adjusting thickness — a fake coin made from a denser-than-silver base metal needs to be thinner to hit the right weight, and vice versa. Calipers catch this immediately.
Diameters for common silver coinage
Coin
Diameter (mm)
Thickness (mm)
Mercury / Roosevelt Dime
17.91
1.35
Washington / Standing Liberty Quarter
24.26
1.75
Walking Liberty / Franklin / Kennedy Half
30.61
2.15
Morgan / Peace Dollar
38.10
2.40
Trade Dollar (US)
38.10
2.40
British Crown
38.61
2.89
British Florin
28.50
1.85
Voyageur Silver Dollar (CA)
36.07
2.84
8 reales / Caballito peso
39.00
2.50
If a coin is more than ~0.3 mm off-spec on diameter or ~0.2 mm off on thickness, the alarm should go up. Wear changes thickness slightly (more in heavy circulation) but doesn't change diameter.
Pre-1965 silver quarter — non-magnetic; modern clad quarters pull weakly
3 Magnet test
Difficulty: trivial · Tools: strong neodymium (rare-earth) magnet, ~$5 from a hardware store
Hold the magnet against the coin. Real silver and gold are not magnetic. If the coin sticks to the magnet, even slightly, it's not pure silver or gold — it has iron, steel, or significant nickel content.
The advanced version: hold the magnet to a vertical surface, place the coin against it, and tilt the surface. A real silver coin will slide slowly as the magnet's eddy currents create drag through the silver (silver is highly conductive). A fake will either drop quickly (no eddy effect) or stick (magnetic). The slide test is one of the cleanest visual demonstrations.
✓ Real silverNo attraction to the magnet. Slides slowly down a tilted magnetic surface (eddy current drag).
✗ Fake or non-silverAttracts to magnet (iron/steel core). Or shows no eddy drag (lead, tungsten, brass).
Common cupronickel coinage (post-1965 US dimes/quarters, post-1947 UK silvers, post-1968 Canadian) is slightly magnetic from the nickel content. So a magnetic response on a coin claiming to be "old silver" is a strong fail.
Limitations
Counterfeits made of brass, lead, copper, or tungsten will also be non-magnetic. The magnet test rules out the cheapest fakes (steel core) but doesn't catch the better ones. Combine with weight + dimensions + specific gravity.
A Mercury dime is too small to ping reliably — halves and dollars work best
4 Ping test
Difficulty: medium · Tools: another coin or pencil; smartphone app (optional)
Real silver coins, balanced on a fingertip and gently struck with another coin or a wooden pencil, produce a long, clear, high-pitched ringing tone — the classic "silver ring." Counterfeit coins or base-metal coins produce a duller thud or a short tinny clink that decays quickly.
A free smartphone app (search "Bullion Test" or "Coin Ping Test") can record the tone and compare it to a known-good silver reference. Useful if you don't have a real coin to compare against.
How to do it
Balance the coin on the tip of your index finger, dead center.
Gently tap the edge with another coin (a US quarter works well as a striker), or a wooden pencil.
Listen for a clear, sustained ring lasting at least a second — for larger coins (silver dollars, crowns), the ring can sustain 2–3 seconds.
Pro tip
Practice on coins you know are real before relying on the test. The "real" sound is unmistakable once you've heard it — it's almost bell-like — but you need a baseline.
Limitations
Smaller coins (silver threepence, half dimes) are too small to ping reliably. Reeded edges complicate the tone. Best for half-dollar size and up.
Pure silver, SG 10.49 — the atomic-scale fingerprint that fakes can't match
5 Specific gravity
Difficulty: medium · Tools: kitchen scale, beaker of water, thread or wire, ~5 minutes
The hardest test to fool. Specific gravity (SG) measures density — mass per volume — which is determined by atomic structure. Counterfeits can match weight, dimensions, and even surface appearance, but they almost always miss SG.
SG of common metals
Metal / alloy
SG
Pure silver (.999)
10.49
Sterling silver (.925)
10.36
US 90% coin silver (.900)
10.34
Pure gold (.999)
19.32
22-karat gold (.917)
17.7–17.8
Tungsten (the only metal close to gold)
19.25
Lead
11.34
Copper
8.96
Brass
8.4–8.7
Cupronickel (75/25)
8.92
How to measure
Weigh in air: place coin on the scale, record mass → Wair (g).
Weigh submerged: tie thin thread or fine wire around the coin, suspend so the coin hangs in a beaker of water without touching sides or bottom (the beaker sits on the scale; tare the empty beaker first). Record → Wwater (g).
Compute: SG = Wair ÷ (Wair − Wwater)
Example: a 1964 silver dime weighs 2.50 g in air. Submerged, it reads 2.258 g (the 0.242 g difference is the buoyant force). SG = 2.50 / (2.50 − 2.258) = 2.50 / 0.242 = 10.33 — right on the 10.34 spec for 90% silver.
The tungsten problem
Tungsten has a specific gravity of 19.25 — almost identical to gold (19.32). A tungsten core plated with a thin gold layer can pass the SG test. This is why ultrasonic testing or assay drilling is required for high-value gold bars. For coins, the coin's own thickness limits how much tungsten can be hidden, but be especially careful with large gold bars.
The Trade Dollar — one of the most-counterfeited US silver coins, especially in chopmarked Asian-trade variants
6 Visual / edge inspection
Difficulty: medium · Tools: 10x loupe, the coin spec for the year/mint
The cheapest authenticity check, often the most informative. Look at the coin under magnification and compare against known-real reference photos.
What to look for
Cast seam on the edge. Counterfeit coins are sometimes cast (not struck), and a faint seam runs around the edge where the two mold halves met. Real coins have no seam.
Reed count. Authentic coins have a specific number of reeds on the edge: 118 on a Morgan dollar, 119 on a Washington quarter, 150 on a Walking Liberty half. Counterfeiters frequently miss this. Count the reeds with a loupe or photograph the edge and zoom.
Soft details on the highest-relief points. Counterfeits made from worn dies or low-quality molds show mushy detail on Liberty's hair, eagle feathers, or the date. Real coins, even worn ones, retain sharp transitions where the design has not abraded.
Wrong typography. Counterfeits sometimes get the date or mintmark font subtly wrong. Compare against a high-resolution reference photo of the same date/mint.
Color tone. Real silver tarnishes to a soft gray over decades. Counterfeit silver-plated coins often have a too-bright surface (fresh plating) or develop bright copper or yellow undertones where the plating wears.
"Reverse not aligned with obverse." Most US coins are struck in coin alignment (180° rotation between sides) or medal alignment (0°). Counterfeits sometimes get this wrong.
Pro tip
For any high-value coin, search PCGS or NGC's online photograde galleries for a verified specimen of the same date/mintmark. Side-by-side, fakes usually announce themselves — the proportions, font weight, or detail sharpness will be subtly off.
Field-test checklist
Five-minute authentication routine
Weight: kitchen scale, mint spec lookup. Within 3% → pass.
Dimensions: digital calipers, mint spec lookup. Within 0.3 mm diameter, 0.2 mm thickness → pass.
If anything in 1–4 is off: do specific gravity. Within 0.10 of spec SG (10.34 for 90% US silver, 10.36 for sterling) → pass.
If still ambiguous: ping test, or take to a dealer with an XRF analyzer for ~$5–10 verification.
Where most fakes come from
The two main sources of modern silver-coin counterfeits are mainland Chinese fake-coin factories (which have been making fakes of US Morgan dollars, Trade dollars, Walking Liberty halves, and key dates of every series since the 2000s) and small-time "magician's coin" operations producing silver-plated cupronickel slugs. The former are well-made and require multi-test verification; the latter usually fail the magnet test alone.
The most-counterfeited silver coins to be especially careful with:
Beyond US series: British Trade Dollar, Mexican 8 reales (chopmarked or not), and modern bullion — American Silver Eagles, Canadian Maple Leafs, and Britannias are heavily counterfeited. Modern issues carry anti-counterfeit features (radial lines, micro-engraving, security mintmarks) that real coins should show under a loupe.
For any individual coin worth more than a few hundred dollars, the strongest authentication is a third-party grading service (PCGS, NGC) slab — both companies authenticate before grading, and slabs are tamper-evident.
Sources: US Mint historical specifications · Royal Mint specifications · The Official Red Book of US Coins (Yeoman) · PCGS, NGC published authentication standards.
