How to Tell if Gold is Real: 13 Tests You Can Do at Home
With gold prices at record highs, knowing how to verify authenticity is more important than ever. This comprehensive UK guide explains 13 testing methods you can use at home, the science behind each test, how to read hallmarks, spot fake gold, and when you need professional verification.
Important: No Single Test is Definitive
Sophisticated fakes can pass individual tests. Always combine multiple methods and for high-value items, seek professional XRF testing. Home tests can indicate likely fakes but cannot guarantee authenticity with 100% certainty.
Quick Reference: Which Test to Use
| # | Test | Reliability | Difficulty | Damages? | Cost | Best For |
|---|---|---|---|---|---|---|
| 1 | Visual Inspection & Hallmarks | Medium | Easy | No | £5-£15 | First check on any item |
| 2 | Magnet Test | Low | Easy | No | £5-£10 | Ruling out cheap fakes |
| 3 | Density Test (Water Displacement) | High | Medium | No | £15-£30 | Solid items without gems |
| 4 | Vinegar Test | Medium | Easy | No | £1 | Quick screening test |
| 5 | Ceramic Scratch Test | Medium | Easy | Yes | £2-£5 | Suspected fakes you don't mind scratching |
| 6 | Acid Test | High | Hard | Yes | £50-£80 | Determining exact purity |
| 7 | Ping Test (Sound Test) | Medium | Easy | No | £0 | Coins and bars only |
| 8 | Skin Discolouration Test | Low | Easy | No | £0 | Jewellery you can wear for 48 hours |
| 9 | Float Test | Low | Easy | No | £0 | Quick first check on small items |
| 10 | Makeup / Foundation Test | Low | Easy | No | £5 | Quick check with household items |
| 11 | Lighter / Fire Test | Medium | Medium | No | £5-£10 | Items without gemstones or delicate settings |
| 12 | Bleach Test | Medium | Medium | Yes | £1 | Confirming suspected fakes |
| 13 | Size-to-Weight Ratio Test (Coins) | High | Medium | No | £20-£40 | Gold coins (Sovereigns, Britannias) |
UK Gold Purity & the Karat System
Before testing gold, you need to understand what “real gold” means. Pure 24-carat gold is too soft for most jewellery, so it's alloyed with other metals. The karat system measures purity as a fraction of 24 parts, while the millesimal fineness system (used in UK hallmarks) expresses parts per thousand.
| Karat | Fineness | Gold % | Typical Alloy | Density (g/cm³) | Primary UK Usage |
|---|---|---|---|---|---|
| 9ct | 375 | 37.5% | Copper, Silver, Zinc | 11.3 - 12.7 | Everyday high-durability jewellery |
| 14ct | 585 | 58.5% | Copper, Silver | 13.0 - 14.5 | Common in European/US imports |
| 18ct | 750 | 75.0% | Silver, Copper, Palladium | 15.2 - 15.9 | High-end jewellery and watches |
| 22ct | 916 | 91.6% | Copper, Silver | 17.7 - 17.9 | Sovereigns, traditional Asian jewellery |
| 24ct | 999 | 99.9% | Minimal impurities | 19.3 | Investment bars, modern Britannias |
Why Does the UK Use 9ct as the Minimum?
The UK introduced the 9-carat standard in 1854 during the Victorian era to meet demand for affordable luxury jewellery. While the US and Canada use 10ct as their minimum, the UK's 9ct standard (37.5% gold) has remained ever since. The original 12ct and 15ct standards were phased out in 1932 and replaced by 14ct to align with international trade.
Understanding UK Hallmarks
The hallmark is your first and most reliable tool for identifying real gold in the UK. Under the Hallmarking Act 1973, it's a criminal offence to describe an un-hallmarked item as gold if it weighs 1 gram or more and is being sold in trade.
The Four Pillars of a UK Hallmark
1. Sponsor's Mark
The unique mark of the individual or firm that submitted the item for hallmarking. Consists of at least two initials within a specific shield shape.
2. Metal & Fineness Mark
Shows the gold content as a millesimal number within an oval surround: 375 (9ct), 585 (14ct), 750 (18ct), 916 (22ct), or 999 (24ct).
3. Assay Office Mark
Identifies which of the four UK offices tested the item. Each has a distinctive symbol that's been used for centuries.
4. Date Letter (Optional)
No longer legally required since 1999 but still frequently applied. Uses a specific letter font and surround to denote the year of assay.
UK Assay Office Symbols
| Assay Office | Symbol | Operating Since |
|---|---|---|
| London | Leopard's head | 1327 |
| Birmingham | Anchor | 1773 |
| Sheffield | Yorkshire rose | 1773 |
| Edinburgh | Castle | 1457 |
How to Spot Fraudulent Hallmarks
- ! “Blobby” or shallow impressions — genuine hallmarks are crisp, struck with high-pressure dies
- ! Non-standard numbers — e.g. “378” instead of “375” or “752” instead of “750”
- ! Inconsistent spacing between the symbols in the hallmark
- ! Mismatched components — a genuine 18ct clasp on a plated chain (a common counterfeiter trick)
For a complete guide to reading UK hallmarks, see our UK Gold Hallmarks Guide.
Types of Fake & Imitation Gold
Not everything that looks like gold is gold. Understanding the different types of gold-coloured items helps you know what to test for and what your item might actually be.
Gold Plated (GP, GEP, HGE)
Negligible ValueA base metal core (copper or brass) coated in an extremely thin layer of gold, often less than 0.5 microns. Wears through at high-friction points like edges and clasps, revealing darker base metal beneath.
Gold Filled (GF) & Rolled Gold (RGP)
Minimal ValueA thicker layer of gold mechanically bonded to a base metal core. The gold layer must be at least 5% (1/20) of total weight. More durable than plating but still not solid gold.
Gold Vermeil
Silver ValueGold plating over a sterling silver base, with a minimum gold thickness of 2.5 microns. Worth more than base-metal plating due to the silver content, but not solid gold.
Stamps That Indicate Non-Solid Gold
| Stamp | Meaning | Status |
|---|---|---|
| GP | Gold Plated | Not Solid Gold |
| GEP / GE | Gold Electroplated | Not Solid Gold |
| HGE / HGP | Heavy Gold Electroplate | Not Solid Gold |
| GF | Gold Filled | Not Solid Gold |
| RGP | Rolled Gold Plate | Not Solid Gold |
| 1/20 | 5% Gold by Weight | Gold Filled |
| 925 | Sterling Silver | Not Gold (often Vermeil) |
All 13 Testing Methods Explained
⚗️ The Science
UK law requires gold items over 1g to be hallmarked by an assay office. These stamps verify the gold has been independently tested. Visual inspection can also reveal plating wear-through.
What You Need
- Magnifying glass or 10x loupe
- Good lighting
Step-by-Step
- 1Find the hallmark - check inside rings, near clasps, on the back of pendants
- 2Look for a 3-digit number: 375 (9ct), 585 (14ct), 750 (18ct), 916 (22ct), 999 (24ct)
- 3Check for an assay office mark: leopard's head (London), anchor (Birmingham), rose (Sheffield), castle (Edinburgh)
- 4Examine edges, clasps, and high-wear areas for discolouration or a different metal showing through
How to Interpret Results
Valid UK hallmarks are a strong indicator of genuine gold. However, hallmarks can be forged, so combine with other tests. Wear-through revealing a different colour metal indicates plating.
Limitations
- ⚠️ Hallmarks can be faked (though this is illegal)
- ⚠️ Items under 1g don't require hallmarking
- ⚠️ Foreign gold may have different marking systems
- ⚠️ Worn items may have illegible hallmarks
⚗️ The Science
Gold is diamagnetic - it's not attracted to magnets and shows very weak repulsion. Ferromagnetic metals like iron and nickel are strongly attracted. If an item sticks to a magnet, it contains these metals and isn't solid gold.
What You Need
- Strong neodymium magnet (not a fridge magnet)
Step-by-Step
- 1Get a strong neodymium magnet (available online cheaply)
- 2Hold the magnet close to your gold item
- 3Observe any attraction or movement
How to Interpret Results
Strong attraction = definitely not solid gold. No attraction = possible gold, but not proof (copper, brass, and lead are also non-magnetic). This test rules out fakes but doesn't confirm authenticity.
Limitations
- ⚠️ Many fake materials (copper, brass, lead, aluminium) are also non-magnetic
- ⚠️ Gold-plated items with non-magnetic cores will pass
- ⚠️ Clasps and springs may contain magnetic metals even on real gold jewelry
- ⚠️ Only rules out iron/nickel-based fakes
⚗️ The Science
Gold is one of the densest metals at 19.3 g/cm³. This is extremely difficult to fake - common counterfeit materials have much lower densities. By measuring weight and water displacement, you can calculate density precisely.
What You Need
- Digital scale (0.1g accuracy)
- Glass of water
- String or thin wire
- Calculator
Step-by-Step
- 1Weigh the item dry and record the weight in grams (W₁)
- 2Fill a glass with water and place it on the scale, then zero/tare the scale
- 3Suspend the item fully in the water using string (don't let it touch the bottom or sides)
- 4Record the weight shown on the scale - this equals the water displaced (W₂)
- 5Calculate density: Density = W₁ ÷ W₂
How to Interpret Results
Compare your result to the expected density for that purity. Pure 24ct gold = 19.3 g/cm³, 22ct = 17.7-17.9, 18ct = 15.2-15.9, 14ct = 13.0-14.5, 9ct = 11.3-12.7. Results within 5% of expected values indicate genuine gold.
Limitations
- ⚠️ Hollow items or those with gemstones give inaccurate results
- ⚠️ Requires reasonably accurate scales
- ⚠️ Small items have higher measurement error
- ⚠️ Tungsten has similar density to gold (extremely rare in fakes but possible)
⚗️ The Science
Gold is a 'noble metal' - chemically inert and resistant to corrosion. Vinegar (acetic acid) doesn't react with gold but will react with base metals like copper, zinc, and iron, causing discolouration or bubbling.
What You Need
- White vinegar
- Glass or ceramic dish
- Cotton bud (optional)
Step-by-Step
- 1Clean the item to remove dirt or oils
- 2Place the item in a glass dish or apply vinegar directly with a cotton bud
- 3Cover the item with white vinegar
- 4Wait 15 minutes
- 5Observe any colour change or reaction
How to Interpret Results
No change = consistent with real gold. Discolouration, bubbling, or green tinge = base metals reacting, indicates fake or heavily plated gold. The reaction happens because vinegar dissolves the oxide layer on base metals.
Limitations
- ⚠️ Low-carat gold (9ct) contains 62.5% base metals but usually won't react noticeably
- ⚠️ Gold plating thick enough may protect base metal temporarily
- ⚠️ Test doesn't work on all fake alloys
- ⚠️ Not definitive proof on its own
⚗️ The Science
When gold is dragged across unglazed ceramic, it leaves a gold-coloured streak because it's softer than the ceramic. Many fake gold alloys leave black, grey, or greenish marks instead.
What You Need
- Unglazed ceramic tile or plate (the rough underside works)
Step-by-Step
- 1Find an unglazed ceramic surface (the bottom of a ceramic plate or tile)
- 2Firmly drag the gold item across the surface
- 3Examine the colour of the streak left behind
How to Interpret Results
Gold streak = consistent with real gold. Black or grey streak = likely pyrite ('fool's gold') or other fake material. Note: this test can scratch your item.
Limitations
- ⚠️ Can scratch and damage genuine gold items
- ⚠️ Gold-plated items may leave a gold streak initially
- ⚠️ Doesn't determine purity, only that gold is present
- ⚠️ Some gold alloys may leave slightly different coloured streaks
⚗️ The Science
Nitric acid dissolves most metals but not gold. Testing kits contain acids calibrated for different purities - if a scratch dissolves under a specific acid, the gold is below that purity. Professional method used by many dealers.
What You Need
- Gold testing acid kit (different acids for different carats)
- Black touchstone
- Safety equipment (gloves, goggles)
Step-by-Step
- 1Put on safety gloves and goggles
- 2Rub the gold firmly on the black touchstone to leave a visible mark
- 3Apply the lowest carat acid (usually 9ct) to the mark
- 4If the mark remains, test with higher carat acids until it dissolves
- 5The highest acid that doesn't dissolve the mark indicates the purity
How to Interpret Results
Mark dissolves in 9ct acid = below 9ct (not UK legal gold). Mark survives 18ct acid but dissolves in 22ct acid = 18ct gold. Mark survives all acids = 22ct or higher.
Limitations
- ⚠️ Requires purchasing testing kit (£50-80)
- ⚠️ Acids are corrosive - safety precautions essential
- ⚠️ Leaves a small scratch on the item
- ⚠️ Heavy gold plating can give false positives
- ⚠️ Requires some practice to interpret correctly
⚗️ The Science
Gold has a distinctive acoustic signature. When a gold coin or bar is struck, it produces a long, high-pitched ringing sound due to gold's elasticity and density. Fake metals produce a duller, shorter sound.
What You Need
- Another piece of metal or coin to strike against
Step-by-Step
- 1Hold the gold coin or bar loosely on your fingertip (don't grip it)
- 2Gently tap it with another coin or small metal object
- 3Listen to the sound produced
How to Interpret Results
Long, high-pitched ring that sustains for 1-2 seconds = consistent with gold. Dull thud or short clunk = likely not gold. Works best with coins and bars; less reliable for jewelry.
Limitations
- ⚠️ Only works well with coins and bars, not jewelry
- ⚠️ Requires some experience to recognise the 'right' sound
- ⚠️ Alloyed gold (9ct, 14ct) sounds different from pure gold
- ⚠️ Some fakes are designed to pass this test
⚗️ The Science
Acids in human skin react with base metal alloys (particularly copper) to produce green or black oxides. Real gold is chemically inert and won't stain skin, even after extended wear.
What You Need
- None - just wear the item
Step-by-Step
- 1Clean the gold item and your skin
- 2Wear the item continuously for 24-48 hours
- 3Include periods of exercise or hand-washing to increase moisture exposure
- 4Remove and examine the skin beneath for any discolouration
How to Interpret Results
No marks = consistent with real gold. Green marks = copper oxide from base metals beneath plating. Black marks = reaction between base metals and skin acids. Any discolouration suggests the item is plated or not gold.
Limitations
- ⚠️ Takes 24-48 hours for results
- ⚠️ Some people's skin chemistry reacts more than others
- ⚠️ 9ct gold contains base metals but typically won't cause reactions
- ⚠️ Cosmetics or lotions can cause false reactions
- ⚠️ Not practical for bars or coins
⚗️ The Science
This is a simplified density check. Gold has an exceptionally high density (19.3 g/cm³ for 24ct) which means it sinks rapidly in water. Lighter metals used in fakes will sink more slowly or float.
What You Need
- Glass or bowl of water
Step-by-Step
- 1Fill a clear glass or bowl with water
- 2Gently drop the gold item into the water
- 3Observe how quickly it sinks
How to Interpret Results
Sinks immediately to the bottom = consistent with gold (gold is very dense). Floats, hovers, or sinks slowly = not gold. However, many fake materials also sink, so this only catches the lightest fakes.
Limitations
- ⚠️ Many counterfeit materials also sink in water
- ⚠️ Hollow items will float regardless of material
- ⚠️ Less reliable than the full density test
- ⚠️ Only catches the most obvious fakes
⚗️ The Science
Liquid foundation contains fine mineral particles that act as a mild abrasive. Gold is soft enough that rubbing it against these particles shears off microscopic gold particles that appear as a black or dark streak.
What You Need
- Liquid foundation makeup
Step-by-Step
- 1Apply a thin layer of liquid foundation to the back of your hand
- 2Allow the foundation to dry completely
- 3Firmly rub the gold item across the dried foundation
- 4Check for a black or dark streak where the gold made contact
How to Interpret Results
A visible black streak = consistent with real gold (microscopic gold particles). No streak = may suggest the item is not gold or is heavily alloyed. This test is less reliable than others and works best as a quick screening.
Limitations
- ⚠️ Not all foundations produce the same results
- ⚠️ Heavily alloyed gold may not produce a clear streak
- ⚠️ Some fake materials may also leave marks
- ⚠️ Should never be used as a sole test
⚗️ The Science
Gold has a very high melting point (1,064°C) and does not oxidise under flame. A standard butane lighter reaches about 1,000°C - hot enough to damage base metals but not to melt gold. Fake gold will darken or change colour as base metals oxidise.
What You Need
- Butane lighter
- Metal tongs or pliers
Step-by-Step
- 1Hold the item securely with metal tongs (never your fingers)
- 2Use a butane lighter to heat a small area for about 60 seconds
- 3Observe any colour changes during and after heating
- 4Allow to cool completely before handling
How to Interpret Results
Real gold gets brighter and may glow slightly but returns to its original colour when cooled. Fake gold turns black, produces smoke, or shows permanent discolouration. Plated items may show the base metal colour as plating burns away.
Limitations
- ⚠️ Can damage gemstones, soldered joints, and delicate settings
- ⚠️ Risk of burns - always use tongs
- ⚠️ Some gold alloys (especially lower carat) may show slight discolouration
- ⚠️ Not suitable for items with sentimental value
- ⚠️ Won't detect gold-filled items quickly
⚗️ The Science
Chlorine in bleach is one of the few chemicals that reacts with gold alloys - but it aggressively attacks base metals far more. Fake gold will show rapid, dramatic tarnishing, while high-purity gold remains largely unaffected.
What You Need
- Household bleach (sodium hypochlorite)
- Glass or ceramic bowl
- Rubber gloves
Step-by-Step
- 1Put on rubber gloves for safety
- 2Place the item in a glass or ceramic bowl
- 3Pour enough household bleach to cover the item
- 4Wait 15 minutes and observe
- 5Remove, rinse thoroughly with water, and dry
How to Interpret Results
No change or minimal dulling = consistent with real gold. Significant bubbling, dramatic colour change, or tarnishing = fake gold or base metal. Note: even real 9ct gold may show mild dulling due to its high base-metal content.
Limitations
- ⚠️ Can damage low-carat gold settings and finishes
- ⚠️ Chlorine can damage delicate jewellery permanently
- ⚠️ Not suitable for items with gemstones
- ⚠️ Requires well-ventilated area - bleach fumes are harmful
- ⚠️ Should be treated as a destructive test
⚗️ The Science
Bullion coins are struck to exact specifications by mints. Because gold's density is so specific, it is nearly impossible to match both the correct weight and dimensions using any other metal except tungsten. Even small discrepancies indicate a fake.
What You Need
- Digital calipers (0.01mm accuracy)
- Precision digital scale (0.01g accuracy)
Step-by-Step
- 1Weigh the coin on a precision scale and record to 0.01g
- 2Measure the diameter with digital calipers
- 3Measure the thickness with digital calipers
- 4Compare all three measurements against official Royal Mint specifications
- 5Check that weight, diameter, and thickness all match simultaneously
How to Interpret Results
All measurements within tolerance = consistent with genuine coin. Any discrepancy of 0.5mm in diameter, 0.1mm in thickness, or 0.1g in weight is a significant red flag. Counterfeiters can match one or two measurements but rarely all three.
Limitations
- ⚠️ Only works for coins and bars with published specifications
- ⚠️ Requires quality measuring equipment
- ⚠️ Worn coins may show slight variations from mint specs
- ⚠️ Tungsten-core fakes can match weight and size (very rare)
Density Reference Tables
The density test is the most reliable home method because gold's density is extremely difficult to fake. Use these tables to interpret your results.
| Carat | Fineness | Density (g/cm³) |
|---|---|---|
| 24ct | 999 | 19.3 |
| 22ct | 916 | 17.7 - 17.9 |
| 18ct | 750 | 15.2 - 15.9 |
| 14ct | 585 | 13.0 - 14.5 |
| 9ct | 375 | 11.3 - 12.7 |
| Material | Density (g/cm³) | Notes |
|---|---|---|
| Brass | 8.4 - 8.7 | Common in fake jewelry |
| Copper | 8.9 | Used in gold plating base |
| Lead | 11.3 | Similar to 9ct - can fool basic tests |
| Tungsten | 19.3 | Same as gold - rare but sophisticated fakes |
| Steel | 7.8 | Magnetic - fails magnet test |
Warning: Tungsten Fakes
Tungsten has almost identical density to gold (19.3 g/cm³), making it the material of choice for sophisticated fakes. Tungsten-core gold bars have been discovered. The density test cannot detect these. For high-value bars, professional XRF or ultrasound testing is essential.
UK Gold Coin Verification Specs
If you're testing gold coins, compare against these official Royal Mint specifications. Because gold's density is so specific, counterfeiters cannot match all three measurements (weight, diameter, thickness) simultaneously with any other metal except tungsten.
| Coin | Purity | Weight | Diameter | Thickness |
|---|---|---|---|---|
| Gold Sovereign | 22ct (916) | 7.98g | 22.05mm | 1.52mm |
| Half Sovereign | 22ct (916) | 3.99g | 19.30mm | 1.02mm |
| Britannia (1oz) | 24ct (999.9) | 31.21g | 32.69mm | 2.80mm |
Tolerance guide: A discrepancy of more than 0.5mm in diameter, 0.1mm in thickness, or 0.1g in weight is a significant red flag. Worn or circulated coins may show slight variations, but modern bullion coins should match specs closely.
Common Gold Scams in the UK
The UK market has seen a rise in sophisticated counterfeits. Understanding these scams is your best defence when buying gold privately.
Tungsten has a density (19.25 g/cm³) nearly identical to gold (19.32 g/cm³). Sophisticated fraudsters drill out genuine gold bars, fill them with tungsten rods, and reseal with a thin gold cap. These bars pass simple weight and density tests.
Protection: Only buy bars from LBMA-approved refiners with matching serial numbers. For secondary market bars, insist on ultrasonic testing or a full XRF report checking core consistency.
Sovereigns are frequently faked using 9ct gold or brass with gold plating to match the 22ct colour. Fake Britannias are rarer but exist.
- ! Blurry details on the monarch's hair or St George design
- ! A “tinny” sound when dropped (use the ping test)
- ! Weight or dimensions outside Royal Mint specs
- ! Non-existent date/mint combinations (e.g. London Sovereign from a year they weren't produced)
Buying gold from Gumtree, Facebook Marketplace, or car boot sales carries extremely high risk. Common tactics include:
- ! Using “restrike” as a euphemism for counterfeit
- ! Providing forged certificates from non-existent labs
- ! Pressure tactics (“other buyers are interested”)
- ! Refusing to allow testing before purchase
Legal position: Selling fake gold as real is a breach of the Fraud Act 2006, punishable by up to 10 years in prison. If you suspect you've been sold fake gold, report it to Action Fraud and your local Trading Standards office.
When to Seek Professional Testing
- ✓ Low-value items you're curious about
- ✓ Initial screening before selling
- ✓ Checking inherited jewelry
- ✓ Ruling out obvious fakes
- ✓ Educational purposes
- ! Items worth over £500
- ! Gold bars (tungsten fake risk)
- ! Before major purchases
- ! Insurance valuations
- ! When home tests give conflicting results
XRF (X-Ray Fluorescence) Testing
The gold standard for testing. Non-destructive, determines exact metal composition in seconds. Available at assay offices, reputable jewellers, and gold dealers. Typical cost: £15-50 per item.
UK Assay Offices
The four UK assay offices (London, Birmingham, Sheffield, Edinburgh) offer “Special Assay” services for the public. Standard assay: ~£40. Express 1-hour service: ~£90. Hallmark verification: ~£25. They can also hallmark unhallmarked items.
Reputable Gold Dealers
Most dealers will test items for free if you're considering selling to them. Find dealers in your area using our dealer directory.
For serious collectors or frequent buyers, consumer-grade electronic testers are a worthwhile investment:
Sigma Metalytics Precious Metal Verifier
Measures electromagnetic resistivity. Can “see through” gold plating to detect tungsten or copper cores in coins and bars.
£900 - £1,500
GoldScreenPen / Auracle
Measures surface conductivity. Excellent for identifying the carat of jewellery but can be fooled by very thick plating.
£350 - £600
Red Flags: Signs of Fake Gold
Visual Warning Signs
- !Discolouration or green/black marks
Base metals oxidising beneath the surface
- !Different colour visible on edges or clasps
Gold plating wearing through to base metal
- !No hallmark on items that should have one
UK law requires hallmarks on gold over 1g
- !Blurry or poorly defined hallmarks
Genuine hallmarks are crisp and clear
Behavioural Warning Signs
- !Price too good to be true
Gold has a market price - big discounts are suspicious
- !Seller refuses testing
Legitimate sellers welcome verification
- !Leaves green marks on skin
Copper oxide from base metal - not real gold
- !Feels unusually light
Gold is dense - lightness suggests base metal
Frequently Asked Questions
Does real gold stick to a magnet?
No, real gold is not magnetic and will not stick to a magnet. If your gold item is attracted to a strong neodymium magnet, it contains ferromagnetic metals like iron or nickel and is not solid gold. However, passing the magnet test doesn't prove gold is real - many fake metals like copper and brass are also non-magnetic.
How do you test gold with vinegar?
Apply a few drops of white vinegar to the gold item and wait 15 minutes. Real gold won't change colour or react because gold is chemically inert. Fake gold or gold-plated items may discolour, bubble, or develop a greenish tinge as the vinegar reacts with base metals like copper and zinc.
How can you tell if gold is real by looking at it?
Look for official UK hallmarks (375, 585, 750, 916, 999) which indicate independently tested gold. Check edges, clasps, and high-wear areas with a magnifying glass for discolouration or a different metal showing through. Real gold has a consistent warm yellow colour (or white/rose depending on alloy) and doesn't tarnish or turn green.
What is the most accurate way to test gold at home?
The density test (water displacement method) is the most accurate home method. Gold has a very high density (19.3 g/cm³ for pure gold) that is extremely difficult to fake. By weighing the item and measuring its water displacement, you can calculate density and compare it to known gold values. However, professional XRF testing remains the gold standard.
How to tell if gold is real with a lighter?
Hold the gold item with metal tongs and heat it with a butane lighter for about 60 seconds. Real gold has a high melting point (1,064°C) and doesn't oxidise under flame - it will get brighter and hotter but won't change colour. Fake gold or base metals will darken, turn black, or produce smoke. Be careful: this test can damage gemstones and delicate settings.
Is unmarked gold real?
Unmarked gold can be real but requires additional testing. Under the Hallmarking Act 1973, gold items over 1 gram sold in trade must be hallmarked in the UK. However, items under 1g are exempt, foreign gold may lack UK hallmarks, and very old or hand-crafted pieces may have worn or illegible hallmarks. Use multiple home tests to verify unmarked gold.
What does 375 mean on gold?
The number 375 is a millesimal fineness mark meaning the item contains 375 parts per thousand of pure gold - equivalent to 9 carat (37.5% gold). This is the minimum legal gold standard in the UK. Other common marks: 585 (14ct, 58.5%), 750 (18ct, 75%), 916 (22ct, 91.6%), and 999 (24ct, 99.9%).
Does real gold turn skin green?
Real solid gold should not turn your skin green. Green marks are caused by copper oxide forming when the copper in base metals reacts with skin acids and moisture. If gold-coloured jewellery leaves green marks, it's likely gold-plated over a copper or brass base, not solid gold. Even 9ct gold (62.5% base metals) shouldn't cause green discolouration.
How can I test gold at home without acid?
Several effective non-acid tests exist: the magnet test (gold isn't magnetic), the density/water displacement test (most accurate non-destructive method), visual hallmark inspection, the vinegar test (gold doesn't react), the float test (gold sinks immediately), the skin discolouration test (wear for 48 hours), and the ping test for coins. Combining 3-4 of these gives a reliable indication.
What is the difference between gold plated and solid gold?
Solid gold is a gold alloy throughout the entire piece (e.g., 9ct is 37.5% gold all the way through). Gold-plated items have a thin layer of gold (often less than 0.5 microns) over a base metal like copper or brass. Plated items are stamped GP, GEP, or HGE and have negligible scrap value. Solid gold carries a hallmark with its fineness (375, 585, 750, etc.) and retains significant value.
Will fake gold turn green?
Fake gold or very low-quality gold-plated items can turn green or leave green marks on skin. This happens when copper in the base metal oxidises. Real solid gold (even 9ct) should not turn green, though it may tarnish slightly over time. Green discolouration is a strong indicator of fake or plated gold.
Where can I get gold tested professionally in the UK?
In the UK, you can get gold professionally tested at the four Assay Offices (London, Birmingham, Sheffield, Edinburgh) for around £40 standard or £90 express service. Reputable high-street jewellers with XRF machines typically charge £15-50 per item. Many gold dealers test for free if you're considering selling. Check our dealer directory for trusted local options.
Can fake gold pass the density test?
Only tungsten can consistently fool the density test, as it has nearly identical density to gold (19.3 g/cm³). Tungsten-core fakes are rare, expensive to produce, and mainly target high-value gold bars rather than jewellery. All other common counterfeit materials (brass, copper, lead, steel) have distinctly different densities that the test will catch.
How do professionals test gold?
Professionals use X-ray Fluorescence (XRF) analysers which determine the exact composition of metals without damaging the item. XRF machines provide definitive results in seconds. UK Assay Offices and reputable dealers use this technology. Some also use electronic testers like the Sigma Metalytics Precious Metal Verifier or acid testing kits.
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Related Guides
Learn to read hallmarks, identify assay office symbols, and understand purity marks.
Read Guide →Understand 9ct vs 18ct vs 24ct, what the numbers mean, and how purity affects value.
Read Guide →Step-by-step guide to selling your gold jewelry and getting the best price.
Read Guide →Sources and References
Gold density and physical properties: CRC Handbook of Chemistry and Physics; LBMA.
UK hallmarking requirements: The Hallmarking Act 1973. Source: legislation.gov.uk
Assay office testing information and pricing: London Assay Office
Sovereign and Britannia specifications: The Royal Mint
Fraud Act 2006: legislation.gov.uk
Last updated: February 2026
Founder & Market Researcher
Taro has been actively investing in precious metals and financial markets for over 15 years. Frustrated by the lack of transparent, accurate gold pricing information in the UK, he built London Gold Exchange as a data-driven resource for fellow investors. The site combines real-time market data, verified dealer information from 242+ UK businesses, and insights drawn from years of hands-on experience in the gold market.
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Disclaimer: Home testing methods provide indications but cannot guarantee gold authenticity with 100% certainty. For high-value items or definitive verification, seek professional XRF testing from an assay office or reputable dealer. The acid test involves corrosive chemicals and the lighter test involves open flame - always use appropriate safety equipment. The bleach test can damage jewellery permanently. Information current as of February 2026.
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