How to Check Gold Purity at Home
Table of Contents
Ravi, a two-wheeler mechanic in Tumakuru, inherited a mixed box of jewellery, some pieces hallmarked, some older than any stamp, and wanted a rough idea of what was real before deciding what to do with it. Knowing how to check gold purity at home gives exactly that: a good directional answer from the hallmark and a handful of household tests, though only a certified assay gives the definitive figure, which is also what a Gold Loan branch performs before lending against any piece. This guide explains karats and fineness with a reference table, then walks through five home methods, hallmark reading with HUID verification, the magnet, vinegar, float and ceramic tests, rating each for reliability, and closes with when the professional assay becomes necessary.
What Gold Purity Means: Karats and Fineness Explained
Karat counts purity out of 24 parts; fineness counts it out of 1,000. Same fact, two scales.
|
Karat |
Fineness |
Gold content |
|
24K |
999 |
99.9% |
|
22K |
916 |
91.6% |
|
18K |
750 |
75% |
|
14K |
585 |
58.5% |
|
9K |
375 |
37.5% |
Note: All figures are indicative. Actual amounts, fees, coverage percentages, and eligibility criteria may vary depending on the lender, borrower profile, loan category, and applicable guidelines at the time of application.
Most Indian jewellery is 22K or 18K; 24K is largely coins and bars, being too soft to wear.
Method 1: Read the BIS Hallmark (Most Reliable)
The hallmark is the only home method that gives a certified figure. On jewellery hallmarked under the current system, look for three marks: the BIS logo, a small triangle; the purity grade with fineness, such as 22K916; and the HUID, a six-character alphanumeric code unique to the piece. Pieces hallmarked before the 2021 changeover may instead carry the older four-mark format, with the assay centre's and jeweller's marks alongside the logo and fineness, and remain genuine hallmarked gold. Verification takes half a minute: open the BIS Care app, choose Verify HUID, enter the code, and the registered purity, jeweller and assay centre return. Reliability: high, the certified ceiling of home checking. The caution: stamps can be faked on cheap pieces, which is exactly what the HUID lookup catches, since a forged code returns nothing.
Method 2: The Magnet Test
Hold a strong magnet near the piece. Gold is not magnetic, so genuine gold will not move; attraction means iron or steel content and settles the question negatively. Reliability: low to medium, and only in one direction, because copper, brass and most alloys are also non-magnetic, so passing the magnet proves nothing about purity. Use it as a thirty-second first screen that can fail a piece, never pass one.
Method 3: The Vinegar Test
Place a few drops of white vinegar on an inconspicuous spot and wait five minutes. Gold does not react: no colour change, no darkening. A surface that darkens or turns greenish contains base metals near the surface, typical of plated or heavily alloyed pieces. Rinse with water afterwards. Reliability: medium, good at exposing plating and cheap alloys, less able to distinguish 18K from 22K, where the gold content is high enough to mask the reaction. Safe for most solid jewellery.
Method 4: The Float Test
Fill a glass with water and drop the piece in. Gold is extraordinarily dense, 19.3 grams per cubic centimetre, so solid gold sinks immediately and decisively. A piece that floats or hovers is plated or base metal. Reliability: medium, best on coins and small solid items; the known failure mode is hollow or intricately worked jewellery, which can behave oddly in water despite being genuine gold. A sink proves density, not purity grade.
Method 5: The Ceramic Scratch Test
Rub the piece gently across an unglazed ceramic tile. Gold leaves a yellow-gold streak; fake or plated items leave a black or grey one. Reliability: medium. The caution outranks the method here: the test abrades the piece, so keep it off antique, engraved, enamelled or plated jewellery entirely, use the lightest touch on a hidden edge if used at all, and skip it for anything with heirloom or resale value. The streak answers one question and costs a little surface to ask it.
When Home Tests Are Not Enough: Professional Assay and Gold Loans
Home methods sort the obvious fakes from the plausible gold; the definitive figure comes from professional assay. Seek it before selling in quantity, for inherited or unmarked pieces like most of Ravi's box, and before pledging gold for a loan. At a lending branch the assessment uses calibrated electronic assay equipment such as XRF, reads the metal without damaging it, happens in the borrower's presence as RBI rules require, and produces a certificate itemising purity, gross and net weight and value, typically within minutes. Knowing the approximate purity in advance from home checks helps set expectations: lenders accept ornaments typically from 18 carats, value them against the 22-carat benchmark rate, and apply tiered LTV caps of up to 85% for loans up to ₹2.5 lakh, 80% to ₹5 lakh and 75% above, at IIFL Finance branches among others.
Conclusion
Home purity checking is a funnel: the hallmark and HUID certify what they cover, the magnet and vinegar weed out the pretenders, the float and streak tests add supporting evidence, and whatever survives with value at stake goes to a professional assay for the real number. Rate every home result for what it is, directional, not definitive, and never sand down an heirloom for a streak of curiosity. Ravi's box sorted into three hallmarked pieces, two confirmed fakes and four maybes that the branch assay settled in one visit, though his case is an illustration; every piece answers only to its own tested metal, under the guidelines prevailing on the day.
Frequently Asked Questions
What is the most accurate way to check gold purity at home?
Reading the BIS hallmark and verifying the HUID on the BIS Care app, because it is the only home method backed by certification: the six-character code returns the piece's registered purity, jeweller and assay centre, and a fake stamp returns nothing. Every other home test, magnet, vinegar, float, ceramic streak, gives directional evidence with known failure modes. For unmarked or inherited pieces, no home method certifies purity; a professional electronic assay, the kind performed at lending branches, provides the definitive figure.
Does the vinegar test damage gold jewellery?
Genuine solid gold, no; vinegar is a mild acid that gold does not react with, and a rinse afterwards leaves the piece unchanged. The risk sits with pieces that are not solid gold: plated items can discolour where the vinegar contacts base metal, which is the test working, though at cosmetic cost. Keep vinegar away from enamel, stones, lac and antique finishes, apply drops to a hidden spot only, and rinse and dry promptly. When in doubt on a valuable piece, skip it.
What karat of gold is accepted for a gold loan in India?
Ornaments of typically 18 carats and above, with valuation benchmarked to 22 carat, so higher purity earns proportionately more per gram, priced at the lower of the 30-day average and previous day's closing price published by IBJA or a SEBI-recognised exchange. Hallmarks are helpful but not required; the branch assay establishes purity for unmarked heirlooms in the borrower's presence. Coins follow separate rules, qualifying only if bank-sold and 22 carats or above, within a 50-gram cap per borrower.
How can I check gold purity if there is no hallmark?
At home, only directionally: the magnet test can fail a piece outright, vinegar exposes plating, and the float test rewards gold's density, but none of the three certifies a karat grade, and the ceramic streak is best avoided on pieces worth keeping. The real answer for unmarked gold is an electronic assay, XRF-type testing that reads composition without damage, available at lending branches where it is performed in your presence with a certificate itemising the tested purity, weight and value.
Is the magnet test enough to confirm gold is real?
No. The magnet test works in one direction only: attraction proves the piece contains iron or steel and is not solid gold, but non-attraction proves very little, since copper, brass, lead and most jewellery alloys are also non-magnetic. A gold-plated brass bangle passes the magnet as smoothly as a genuine one. Treat it as a quick first filter, then stack further evidence, hallmark and HUID where present, vinegar and float tests otherwise, and rely on professional assay for anything of real value.
Disclaimer : The information in this blog is for general purposes only and may change without notice. It does not constitute legal, tax, or financial advice. Readers should seek professional guidance and make decisions at their own discretion. IIFL Finance is not liable for any reliance on this content. Read more
