A magnet takes ten seconds and rules out a whole class of fakes, but it cannot confirm gold and should never be the last step.
Gold, silver, platinum, and copper are not magnetic, while iron, nickel, cobalt, and many steels are. That makes a simple magnet a useful first filter before a piece ever reaches the tank. This guide describes a short sequence: visual check, magnet test, weight, then densimeter, and explains how to read each result, what the magnet misses, and how clasps and springs can fool the test.
- A strong magnet that grabs a piece is a clear rejection; a piece that is not attracted is not proven to be gold.
- Silver, copper, and brass can show a slow drag on a strong magnet because of eddy currents, which is different from true attraction.
- Steel clasps, springs, and findings can cause false positives on genuine gold pieces.
Use a strong magnet
Neodymium magnets give clear results; weak fridge magnets miss many cases.
Test slide and grab
Distinguish true attraction from the slow drag seen on conductive metals.
Check clasps and springs
Test the body of the piece, not the findings.
Escalate non-magnetic results
Pass the piece to the weight and density steps; magnetism alone proves nothing.
What a magnet can and cannot tell you
Magnets respond strongly to ferromagnetic metals such as iron, nickel, and cobalt. Many base-metal fakes, steel-cored items, and nickel-rich alloys will stick or tug against a strong neodymium magnet. If a piece sticks firmly to the body of the metal, stop and decline. This saves you a tank test and shows quickly that the item is not gold. It is a free, fast step that should happen before weighing in water, particularly for chains and bars that look suspicious or that were bought from unfamiliar sellers.
The limitation is that a lack of attraction proves almost nothing. Gold, silver, platinum, copper, brass, tungsten, and lead are all non-magnetic or very weakly magnetic. A fake made of tungsten or a lead-based core will pass the magnet test without any sign of trouble. Conductive non-magnetic metals such as copper and silver also create a slow, smooth drag as a magnet slides along them, which is caused by eddy currents rather than attraction. That effect can tell you something about the metal, but it is not a reliable identification on its own.
A four-step workflow that adds the densimeter
Step one is a visual check of stamps, wear, and construction. Step two is the magnet: slide a strong magnet across the body of the piece, away from clasps. Step three is the weight in air, which you need anyway, and a quick check against expected weight for the size. Step four is the densimeter, run only on pieces that are solid and not attracted. Record each step on the ticket so the process is documented and can be repeated by another employee.
Interpret the results as a combination. A piece that fails the magnet test is out. A piece that passes the magnet and reads a density consistent with the stamped karat is likely solid and of reasonable quality, but still needs a second method on high-value items. A piece that passes the magnet but reads low is probably hollow, plated, or stone-set. A piece that passes the magnet and reads exactly at gold density on a bar needs ultrasonic or assay checks because tungsten is non-magnetic.
- Test the body of the piece, not the clasp or spring.
- Keep a strong neodymium magnet on a lanyard at the counter.
- Never treat a non-magnetic result as proof of gold.
Workflow summary
The table below shows what each step is good at and what it misses, so staff understand that each step is a filter rather than a proof. Combining the steps catches far more problems than any single one can, and the extra time per piece is only a minute or two.
| Step | Catches | Misses |
|---|---|---|
| Visual check | Wear, stamps, poor finish | Quality fakes |
| Magnet | Steel, nickel, iron cores | Tungsten, lead, copper, brass |
| Weight | Wrong size for weight | Matching-weight fakes |
| Densimeter | Hollow, plated, lead fills | Tungsten, gem-set, voids |
Recommended densimeters for this workflow
| Product | Best for | Price tier | Editor view | Amazon |
|---|---|---|---|---|
| Alfa Mirage GK-300 | Jewelry counters buying solid gold under ~250 g | Premium | Editor assessment: Excellent | Check Latest Price → |
| RODIETO 600 g Gold Purity Densimeter | Pawn and mixed jewelry intake with heavier solid chains | Value | Editor assessment: Strong | Check Latest Price → |
Best Overall for Jewelry Desks
Alfa Mirage GK-300
- Best forJewelry counters buying solid gold under ~250 g
- Price tierPremium
- Editor viewEditor assessment: Excellent
Best Value / Best for Pawn Capacity
RODIETO 600 g Gold Purity Densimeter
- Best forPawn and mixed jewelry intake with heavier solid chains
- Price tierValue
- Editor viewEditor assessment: Strong
Best Overall for Jewelry Desks
Alfa Mirage GK-300
Key takeaways
- Best when solid jewelry stays under ~250 g
- Karat language staff can explain to customers
- Skip if heavy chains already crowd 300 g
Jewelry counters buying solid gold under ~250 g
You regularly buy heavy chains or bars over 300 g
Quick snapshot
Pros
- Karat modes built for gold buying—not a generic lab densimeter UI
- Japan-made brand that shop owners recognize for warranty optics
- Doubles as a gram scale so trade-ins stay on one footprint
- Non-destructive first pass—no acid stains on retail-ready pieces
Cons
- 300 g ceiling fails many pawn-weight solid chains
- Premium price vs generic 600 g Amazon kits
- Still cannot test hollow or gem-set jewelry (physics limit)
- Some buyers complain about learning the water-hang workflow on day one
Why we picked it
Why it earns the badge
We picked the Alfa Mirage GK-300 as the best overall starter for jewelry stores because it is built around karat language, not just a bare density number. On a retail counter, that matters more than most buyers admit on day one. A salesperson can take a solid trade-in, run the air weight and water weight, and talk in K14 / K18 terms the customer already understands—without translating a raw density chart mid-conversation. The Japan-made positioning also helps when an owner asks why you are not buying the cheapest no-name kit on Amazon. Warranty optics and brand familiarity reduce pushback from partners who have seen too many generic electronics fail after a few busy seasons.
Who it is ideal for
This machine is ideal if your solid intake mostly stays under about 250 g: rings, solid bracelets, light scrap lots, and estate pieces that are clearly solid metal. Treat the 300 g ceiling as a hard workflow limit, not a marketing number. If your desk routinely sees thick Cuban chains, stacked scrap bags, or solid pieces that regularly flirt with 280–300 g, capacity—not brand prestige—should win, and you should move to a 600 g shop densimeter before you outgrow the GK-300 mid-purchase.
Who should skip it
Who should skip it: pawn shops with heavy-chain days, coin desks handling bars, budget-first buyers who only need a rough karat band once a week, and anyone who thinks a densimeter will replace acid or XRF for hollow or gem-set goods. Manufacturer guidance is blunt on the physics limits: hollow jewelry, stone-set pieces, and metals with density very close to gold (including tungsten cores in bars) are outside the trustworthy zone. Those are not “bugs” in the GK-300—they are limits of Archimedes testing itself.
What real buyers get wrong
When you dig past star ratings on Amazon-style densimeter listings, the recurring 1-to-3 star themes are rarely “karat mode is fake.” They are operator and expectation problems: air bubbles clinging to textured scrap, the sample touching the tank wall, testing hollow electroformed jewelry that returns falsely low density, missing English manuals on generic kits, and buyers who expected an assay certificate instead of a first-pass screen. Train solid-sample rules on day one, keep distilled water and a soft brush at the tank, and use a written threshold for when density results escalate to XRF. Done that way, the GK-300 becomes a reliable buyer aid on a jewelry desk rather than a mysterious black box that staff avoid after one awkward customer conversation.
Key specs → desk benefits
300 g capacity / 0.01 g weight resolution
Stable enough for solid rings and most bracelets, with gram-scale precision that keeps scrap payouts honest.
K9–K24 karat + purity % modes
Staff can explain a karat band to a customer in one sentence instead of translating raw density charts.
Densimeter + scale in one unit
You avoid buying a separate jewelry scale for intake weighing on the same counter.
Best Value / Best for Pawn Capacity
RODIETO 600 g Gold Purity Densimeter
Key takeaways
- 600 g headroom for pawn-weight solid chains
- Shop-class 0.001 density without lab pricing
- Confirm seller, accessories, and exact capacity
Pawn and mixed jewelry intake with heavier solid chains
You need Japan-brand prestige more than usable capacity
Quick snapshot
Pros
- 600 g headroom covers most solid chain intake
- 0.001 g/cm³ density resolution is the shop-class sweet spot
- Karat / purity / density in one workflow
- Usually ships as a complete tank + hanger kit
Cons
- Generic brand—seller quality and support vary
- Listing titles can be noisy; you must confirm exact capacity
- Not a tungsten-proof bar tester on its own
- Lower brand recognition if ownership wants “made in Japan” optics
Why we picked it
Why it earns the badge
RODIETO’s 600 g class is our best value pick because capacity is the feature that actually saves pawn and mixed jewelry desks from buying twice. A beautiful 300 g branded unit that cannot weigh your heaviest regular chain is a failed purchase—no matter how clean the karat UI looks in the product photos. This kit targets the real workflow: solid scrap, solid chains, fast karat/density/purity screen, and a complete tank + hanger setup so you are not hunting accessories after the box arrives.
Who it is ideal for
Ideal for pawn shops, mixed jewelry buyers, and scrap desks where solid intake regularly lands between 200 g and 500 g. The 0.001 g/cm³ density resolution is the shop-class sweet spot: fine enough for solid karat banding without paying lab-SKU prices. Managers also get a second number (density or purity %) when karat mode looks off, which helps when a second staffer re-checks a disputed piece.
Who should skip it
Skip it if brand prestige is a boardroom requirement—“made in Japan” optics matter in some retail ownership conversations—or if you only ever buy light rings under ~150 g. In that lighter jewelry-only case, a 300 g premium unit may feel cleaner on a glass retail counter and leave more budget for training and distilled-water discipline. Also skip any densimeter as a standalone answer for bullion bars you suspect are tungsten-filled; density alone will not settle that fight.
What real buyers get wrong
Cross-check Amazon seller ratings and the in-box list (scale, tank, hanger, power, any claimed printer) before you checkout. Across generic 600 g densimeter listings, the honest low-star complaints cluster around missing English instructions, accessories that were pictured but not shipped, confusing multi-SKU titles, and buyers who tested hollow or gem-set jewelry then blamed the machine. Those are avoidable with a pre-purchase checklist: confirm capacity on the live listing, screenshot the accessory list, decline hollow/gem-set pieces at intake, and treat the result as a first pass. Do that, and a value 600 g kit like this becomes the workhorse most pawn desks actually need.
Key specs → desk benefits
600 g capacity
Fewer “piece won’t fit” moments on pawn days when solid chains run heavy.
0.001 g/cm³ density resolution
Fine enough for solid scrap karat banding without paying lab-SKU prices.
Karat + purity + density display
Managers can spot-check a second number (density) when karat mode looks off.
Buying decision
Confirm the listing specs for capacity and resolution before you build this workflow.
FAQ
Can a magnet prove a piece is gold?
No. Gold is not magnetic, but neither are many fakes such as tungsten, copper, and lead. A magnet is only a filter for magnetic metals.
Why does my gold chain stick to a magnet?
The clasp or spring ring is probably steel. Test the body of the chain away from findings to avoid false positives.
What type of magnet should I use?
A strong neodymium magnet gives clearer results than a weak magnet, and you should compare against a known piece first.