How to Value, Test & Authenticate Precious Metals

The complete guide with real formulas, real numbers, and live calculators. From calculating junk silver value to spotting fake gold — everything a stacker needs to know.

Last updated: March 2026 · All formulas verified

1 How to Calculate Junk Silver Value

Pre-1965 US dimes, quarters, and half dollars contain 90% silver. Dealers trade them by face value, not by individual coin.

The Coinage Act of 1965, signed by President Lyndon Johnson on July 23, 1965, removed silver from US circulating coinage. Every dime, quarter, and half dollar minted before that date contains 90% silver. These are called "junk silver" because they have no numismatic premium — their value is purely in the metal content.

  1. Count your total face value

    Add up the face value of all pre-1965 coins. 10 dimes = $1.00 face. 4 quarters = $1.00 face. 2 half dollars = $1.00 face. Don't mix 90% coins with 40% Kennedy halves (1965–1970) — those use a different rate.

  2. Multiply by 0.715 (circulated) or 0.723 (uncirculated)

    0.715 oz per $1 face is the industry standard for circulated coins, accounting for silver lost to wear. 0.723 is the theoretical uncirculated weight. On a $1,000 bag, that's an 8-ounce difference worth $240+ at $30/oz.

  3. Multiply by current silver spot price

    Total silver ounces × spot price = melt value. Use a live calculator for real-time accuracy — spot changes every few seconds during market hours.

Melt value = face value × 0.715 × silver spot price
Example: $100 face × 0.715 = 71.5 oz × $80/oz = $5,720
Quick Reference

At $80/oz silver: one dime = $5.72 · one quarter = $14.30 · one half dollar = $28.60 · $1,000 bag = $57,200

Individual Coin ASW Reference

CoinASW (troy oz)PurityGross Weight
Roosevelt/Mercury Dime0.072390%2.50g
Washington Quarter0.180890%6.25g
Walking Liberty/Franklin/Kennedy Half (pre-65)0.361790%12.50g
Morgan/Peace Dollar0.773490%26.73g
Kennedy Half (1965–1970)0.147940%11.50g
War Nickel (1942–1945)0.056335%5.00g
🪙 Junk Silver Calculator — Live →

2 How to Calculate Gold Melt Value by Karat

Every piece of gold jewelry has a karat rating that tells you exactly how much pure gold it contains.

  1. Find the hallmark stamp

    Look on clasps, inner bands, or tags with a jeweler's loupe. Common stamps: 999 (24K), 916 (22K), 750 (18K), 585 (14K), 417 (10K). Under the National Stamping Act (15 U.S.C. §294), false karat marks are illegal in the US.

  2. Weigh the item

    Use a precision scale accurate to 0.1g. Jewelers typically weigh in grams or pennyweight (dwt). 1 troy oz = 31.1035g = 20 dwt. Remove any non-gold components (stones, clasps) if possible.

  3. Calculate pure gold content

    Multiply weight by the karat's purity decimal. 14K = 0.5833, so 15g of 14K = 15 × 0.5833 = 8.75g pure gold. Convert to troy ounces: 8.75 ÷ 31.1035 = 0.2813 ozt.

  4. Multiply by spot price

    0.2813 ozt × gold spot = melt value. This is what the raw gold content is worth — the floor price for the item.

Melt value = weight (g) × karat purity ÷ 31.1035 × gold spot price
Example: 22g of 18K gold = 22 × 0.750 ÷ 31.1035 × $5,000 = $2,654

Karat to Purity Reference

KaratPurity %DecimalHallmark Stamp
24K99.99%0.9999999
22K91.67%0.9167916
18K75.00%0.7500750
14K58.33%0.5833585
10K41.67%0.4167417
What refiners pay

Reputable refiners: 90–98% of melt value. Local jewelers: 80–90%. Pawn shops and "cash for gold" stores: 40–70%. Always know your melt value before selling.

🔥 Gold Melt Calculator — Live →

3 How to Read the Gold-to-Silver Ratio

The GSR tells you how many ounces of silver it takes to buy one ounce of gold — and whether silver or gold is the better buy right now.

  1. Calculate the ratio

    Divide gold spot by silver spot. If gold is $5,000 and silver is $80, the GSR is 62.5. That means it takes 62.5 ounces of silver to equal one ounce of gold in value.

  2. Compare to historical zones

    The Coinage Act of 1792 fixed the ratio at 15:1. The 20th century average is roughly 60:1. The all-time modern high was 127:1 in March 2020 (COVID). These zones give context to the current number.

  3. Make allocation decisions

    Ratio traders use the GSR to rotate between metals without adding new capital — sell gold when silver is cheap (high GSR), buy it back when the ratio normalizes. Even if you don't actively trade, the GSR helps you decide which metal to buy next.

GSR = gold spot price ÷ silver spot price
80+
Buy Silver Zone
Silver historically cheap vs gold
50–80
Neutral Zone
Near historical average (~60)
Below 50
Buy Gold Zone
Gold relatively cheap vs silver
Ratio Trading Example

At GSR 90: sell 1 oz gold → get 90 oz silver. Wait for GSR to drop to 50: swap 90 oz silver → get 1.8 oz gold. Net gain: 0.8 oz gold with zero new dollars spent.

⚖️ Live GSR Tracker →

4 How to Test Gold & Silver Purity at Home

Five methods ranked by reliability and cost. No single test is conclusive — use at least two for confidence.

1. Hallmark Inspection

Look for stamped purity numbers with a jeweler's loupe (10x magnification). 999, 916, 750, 585, 417 for gold. 925 for sterling silver. 999 for bullion silver.

Cost: $8–15 (loupe)
Medium reliability

2. Magnet Test

Hold a strong neodymium magnet against the item. Gold, silver, and platinum are not magnetic. If it sticks, it's fake or plated over a ferrous base metal. Passing doesn't confirm authenticity — many fakes use non-magnetic metals.

Cost: $5–10 (neodymium magnet)
Low — rules out fakes, doesn't confirm real

3. Specific Gravity Test

Weigh in air, then suspended in water. Gold: 19.32 g/cm³. Silver: 10.49. Platinum: 21.45. Tungsten is 19.25 (dangerously close to gold). Best non-destructive test for solid items.

Cost: $30–50 (precision scale)
High reliability

4. Acid Test

Rub item on touchstone, apply acid to the streak. 10K acid dissolves anything below 10K. Each acid strength tests a specific karat. Slightly destructive (leaves a tiny scratch).

Cost: $15–30 (acid kit)
High reliability

5. Electronic / XRF

Sigma Metalytics Precious Metal Verifier ($700+) or handheld XRF gun ($5,000+). Instant, non-destructive, highly accurate. XRF reads the top 10–50 microns of the surface — won't catch deep-core fakes.

Cost: $700–$5,000+
High reliability
Specific Gravity = weight in air ÷ (weight in air − weight in water)
Gold = 19.32 · Silver = 10.49 · Platinum = 21.45 · Tungsten = 19.25 · Copper = 8.96
🔥 Scrap Gold Calculator →

5 How to Detect Fake Gold & Silver

Counterfeiting is a real problem. Here are the specific tests that catch the most common fakes.

Important

Counterfeit precious metals are a criminal offense under 18 U.S.C. §485 (coins) and 18 U.S.C. §487 (gold/silver bars). If you discover counterfeit bullion, report it to the US Secret Service or your local law enforcement. The information below is for authentication purposes only — to protect yourself as a buyer.

Fake gold coins and bars most commonly use a tungsten core plated with real gold. Tungsten's density (19.25 g/cm³) is nearly identical to gold (19.32), so weight alone won't catch it. The telltale signs:

  1. Weigh it precisely

    A genuine 1 oz American Gold Eagle weighs exactly 33.93 grams (it's actually 1.0909 ozt total — the extra weight is copper alloy). Fakes are often off by 0.5–2g. Use a scale accurate to 0.01g.

  2. Measure dimensions

    Counterfeiters rarely get both diameter AND thickness correct simultaneously. A genuine Gold Eagle is 32.70mm diameter × 2.87mm thick. Use calipers. If either dimension is off by 0.5mm+, it's suspect.

  3. The "ping" test (coins)

    Flick the coin and listen. Real gold and silver produce a sustained, high-pitched ring that lasts 2–4 seconds. Fakes produce a dull thud or a short ring. There are even smartphone apps (like CoinPing) that analyze the frequency.

  4. Magnet slide test (silver)

    Tilt a smooth surface at ~45° and place a silver coin on it. Slide a strong neodymium magnet down the surface next to the coin. On real silver, the magnet slides noticeably slower than on the surface alone — this is diamagnetic braking. On fake silver, the magnet slides at normal speed. This is one of the best quick tests for silver.

  5. Specific gravity (gold bars)

    The ultimate home test for bars. Weigh in air, weigh in water, calculate density. A tungsten-filled bar will have slightly wrong density at the decimal level, or the bar dimensions won't perfectly match the expected density for the stated weight.

  6. Buy from trusted sources

    The simplest defense: buy from established dealers (SD Bullion, APMEX, JM Bullion, your local coin shop with a reputation). Avoid random marketplace sellers, especially for high-value items. If the price is significantly below spot, it's almost certainly fake.

Red Flags

Price too good: anything significantly below spot price is almost certainly fake. Weight off: even 0.5g off on a 1 oz coin is suspicious. Wrong sound: thud instead of ring. Magnetic: real precious metals are never magnetic. Seller won't allow testing: walk away.

Common Fake Targets

The most commonly counterfeited items: 1 oz gold bars (easiest to fake with tungsten cores), Chinese Gold Pandas, American Gold Eagles, and 10 oz silver bars. Government-minted coins with intricate designs (Eagles, Maples, Britannias) are harder to counterfeit convincingly than simple bars.

Disclaimer: This guide is for educational and informational purposes only. MetalMetric does not provide financial, investment, legal, or tax advice. Precious metals carry risk — prices fluctuate and past performance does not guarantee future results. Authentication tests described here are informational guides, not guarantees of authenticity. For high-value purchases, consult a professional assayer or use an LBMA-accredited testing facility. Always buy from reputable, established dealers. MetalMetric is not responsible for purchase decisions made based on this content.

Frequently Asked Questions

How much is $1 face value of junk silver worth?

$1.00 face value of circulated 90% silver coins = 0.715 troy oz of pure silver × current spot price. At $80/oz, that's $57.20. Use MetalMetric's junk silver calculator for real-time values.

How can I tell if gold is real without a kit?

Two no-kit tests: (1) Magnet test — gold isn't magnetic. If it sticks, it's fake. (2) Hallmark check — look for stamped numbers (999, 750, 585, 417). Neither is conclusive alone. A specific gravity test ($30 scale + cup of water) is much more reliable.

What is the formula for gold melt value?

Melt value = weight (troy oz) × purity × spot price. For karat gold: weight (grams) × karat decimal ÷ 31.1035 × spot price.

What does a gold-to-silver ratio of 80 mean?

It takes 80 oz of silver to buy 1 oz of gold. Above 80 is historically a "buy silver" signal. Below 50 favors gold. The 20th century average is ~60:1.

How do I spot fake silver coins?

Four methods: (1) Weigh it — genuine Silver Eagle = 31.1g exactly. (2) Magnet slide — real silver causes diamagnetic braking (magnet slides slowly). (3) Ping test — real silver rings; fakes thud. (4) Measure diameter and thickness — counterfeiters rarely get both right.

Calculate Your Melt Values

Put these formulas to work with live spot prices updating every 60 seconds.

Open Melt Calculator — Free

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