Authenticity Test

Fake Gold Detector Guide & Calculator

A step-by-step guide to detecting fake or adulterated gold. Includes the density calculator, magnet test, hallmark check, and acid test guide.

Step-by-Step Fake Gold Tests

1. Hallmark Check (Most Reliable)

Look for a stamped hallmark: 999, 916, 875, 750, 585, 375. In India, look for BIS Hallmark (Bureau of Indian Standards). UK: lion passant + date letter. No hallmark = caution.

2. Magnet Test

Gold is not magnetic. Hold a strong magnet near the piece. Any attraction = likely not gold or heavily alloyed. Note: some fakes use non-magnetic metals (brass, tungsten) and pass this test.

3. Density Test (Most Accurate DIY)

Use the Gold Density Calculator. Weigh in air, then suspend in water. Calculate density = weight-air ÷ (weight-air − weight-water). Pure gold = 19.32 g/cm³.

4. Acid Test (Touchstone)

Scratch the item on a touchstone and apply nitric acid (for 14K/18K) or aqua regia (24K). Color of the streak indicates purity. Requires a test kit (readily available, ~$20). Destructive — leaves a small scratch.

5. XRF Machine (Professional)

X-ray fluorescence (XRF) guns instantly measure exact elemental composition non-destructively. Used by jewelers, pawnshops, and banks. Most accurate test. Ask your local jeweler for an XRF test ($5–$20).

6. The Tungsten Warning

Tungsten has almost the same density (19.25 vs 19.32 g/cm³) as gold and passes magnet + density tests. Tungsten-core gold bars exist. Use XRF or ultrasound testing for bars above 1 oz. Always buy from reputable dealers.

Quick Reference: Tests at a Glance

TestCostCatches tungsten?
HallmarkFreeNo
MagnetFreeNo
DensityFree (scale needed)Barely (0.07 g/cm³ diff)
Acid~$20 kitYes
XRF$5–20 serviceYes

Frequently Asked Questions

What is the most reliable way to test gold at home?+
The combination of hallmark check + density test catches most fakes. For high-value items ($500+), always get an XRF test from a jeweler — it's non-destructive and definitive.
Does real gold stick to a magnet?+
No. Gold is diamagnetic and shows no attraction to a magnet. However, some alloys in gold jewelry may be slightly magnetic, and non-magnetic metals can also fake gold.
What color does gold turn with nitric acid?+
Pure gold shows no reaction with nitric acid. 18K gold leaves a faint green trace. Lower karats show stronger green reactions. Fake gold (brass) turns greenish immediately.
Can gold fade or tarnish?+
24K gold never tarnishes. Lower karat gold (9K, 14K) can develop tarnish over time as the copper/silver alloying metals oxidize. Significant tarnish on supposed 24K suggests it's not genuine.
What is the skin test for gold?+
Rub the gold on your skin or a ceramic tile. Pure gold leaves a yellow mark; fake gold (pyrite, gold-plated brass) often leaves a black or green mark. Not reliable for gold-plated items.