Gold Purity Explained: 24K vs 22K vs 18K vs 14K
Walk into any Canadian gold shop and you'll see numbers everywhere: 24K, 22K, 18K, 14K, .999, .9999, 585, 750. For newcomers, it's alphabet soup. But understanding gold purity is essential — it determines what your gold is actually worth, whether it's GST/HST exempt, and how easily you can resell it.
This guide breaks down the karat system, explains what each purity level means in practice, and shows you how Canadian standards protect buyers.
The Karat System Explained
"Karat" (abbreviated K or kt) measures gold purity on a scale of 24. Pure gold is 24 karat. The karat number tells you how many parts out of 24 are pure gold:
- 24K = 24/24 = 100% pure gold (in practice, 99.9%+)
- 18K = 18/24 = 75% pure gold
- 14K = 14/24 = 58.3% pure gold
- 10K = 10/24 = 41.7% pure gold (the legal minimum to be called "gold" in Canada and the US)
The remaining percentage is made up of alloy metals — silver, copper, nickel, zinc, or palladium — added to make gold harder and more durable, and to alter its colour. Pure 24K gold is relatively soft; you can scratch it with a fingernail. That's why jewellery is rarely 24K.
Decimal and Millesimal Fineness
You'll also see purity expressed as a decimal: .999 means 99.9% pure, .9999 means 99.99% pure. Jewellery often uses a three-digit millesimal stamp: 750 = 18K, 585 = 14K, 417 = 10K. These are just different ways of saying the same thing.
24K vs 22K vs 18K vs 14K: What Each Means for You
24K Gold (99.9%+ Pure)
The purest form commonly available. In Canada, 24K means investment-grade bullion: Gold Maple Leafs (.9999 fine), kilobars, and wafers from accredited refiners. This is the gold that qualifies for the GST/HST exemption and trades closest to the spot price.
24K is too soft for everyday jewellery, though it's popular for ceremonial and high-end pieces in some cultures. If your goal is wealth preservation or investment, 24K bullion is the standard.
22K Gold (91.6% Pure)
Common in 22K jewellery — especially South Asian, Middle Eastern, and East Asian styles widely sold in Vancouver, Toronto, and Surrey. Many classic gold coins are also 22K, including the South African Krugerrand and the American Gold Eagle. These coins contain a full troy ounce of pure gold, but weigh slightly more than an ounce because of the alloy.
22K jewellery is a cultural staple for many Canadian families, but note: as jewellery, it's subject to GST/HST, and resale typically happens at a discount to melt value.
18K Gold (75% Pure)
The sweet spot for fine jewellery in Canada and Europe. Hard enough for daily wear, rich enough in gold content to hold significant intrinsic value. Most high-end Canadian jewellery — engagement rings, luxury watches, designer pieces — is 18K. Stamped "750" in the millesimal system.
14K Gold (58.3% Pure)
The most common jewellery gold in North America. Durable, affordable, and available everywhere. Most mass-market rings, chains, and bracelets sold in Canadian malls are 14K. It holds meaningful gold value but contains less than three-fifths pure gold — something to remember when selling.
10K Gold (41.7% Pure)
The minimum purity that can legally be marketed as gold jewellery in Canada. Common in inexpensive pieces. From an investment standpoint, 10K gold is barely worth considering — you're mostly paying for craftsmanship and retail markup.
Hallmarks: How to Read Gold Stamps
Canadian law requires that gold items carrying a quality mark (like "18K") meet strict standards. Here's how to read the stamps you'll encounter:
- 24K / 999 / 9999 — Investment-grade pure gold
- 22K / 916 — 91.6% pure (common in coins and cultural jewellery)
- 18K / 750 — 75% pure (fine jewellery standard)
- 14K / 585 — 58.3% pure (common North American jewellery)
- 10K / 417 — 41.7% pure (minimum for "gold" labelling)
- GP / EP / RGP — Gold plated, electroplated, or rolled gold plate. These contain only a microscopic layer of gold over base metal. Not solid gold — worth very little as metal.
- Maker's marks — Reputable manufacturers stamp their trademark alongside the purity mark.
Canadian legal note: Under the Precious Metals Marking Act, it's illegal in Canada to mark an item with a gold quality mark unless it genuinely meets that standard (within tight tolerances). Mis-marking is a federal offence. This law is a genuine consumer protection — but it only helps if you buy from legitimate sellers.
Canadian Standards and the GST/HST Threshold
The magic number in Canadian gold investing is 99.5% purity. Gold bars, ingots, wafers, and coins meeting or exceeding this threshold are classified as investment-grade precious metals and are exempt from GST/HST nationwide.
This is why Canadian investors overwhelmingly buy .999 or .9999 fine products: you save the 5–15% tax, and you own the most liquid form of gold on earth. Anything below 99.5% — including all karat jewellery — is taxed normally and trades at a discount to its gold content.
Investment Grade vs. Jewellery Grade: A Direct Comparison
| Feature | Investment Grade (24K bullion) | Jewellery Grade (10K–22K) |
|---|---|---|
| Purity | 99.5%–99.99% | 41.7%–91.6% |
| GST/HST in Canada | Exempt | Taxable |
| Premium over melt value | Low (2–6%) | High (often 100%+) |
| Resale | Near spot price | Below melt value typically |
| Authentication | Sealed, serialized, certified | Requires testing |
| Best for | Wealth preservation | Wearing and gifting |
The takeaway: buy bullion for investment, buy jewellery for enjoyment. Don't confuse the two — jewellery is a terrible investment vehicle because you pay massive retail markups you'll never recover.
How to Test Gold Purity
If you're buying secondhand gold or want to verify what you own, these are the standard methods Canadian dealers use:
Visual Inspection and Hallmarks
Start with the stamp. Then examine the piece: discolouration at edges or worn spots revealing different-coloured metal underneath suggests plating, not solid gold.
Magnet Test (Quick Screening)
Gold is not magnetic. If a "gold" bar sticks strongly to a magnet, it's fake. (Note: this only catches crude fakes — sophisticated counterfeits use non-magnetic metals.)
Acid Test
A jeweller files a tiny notch in an inconspicuous spot and applies nitric acid of known strength. Real gold of the marked karat resists the acid; lower-karat gold dissolves. Inexpensive kits exist, but the test damages the piece slightly — leave it to professionals for valuable items.
Electronic Testing
Devices like the Sigma Metalytics verifier measure electrical conductivity to confirm purity without damaging the item. Most serious Canadian bullion dealers have one and will test in front of you — ask them to.
XRF Analysis
X-ray fluorescence is the gold standard (pun intended): completely non-destructive and precise to the decimal. Refiners and assay offices use XRF machines. If you're selling a large quantity, paying for an XRF assay ($50–$150) is worthwhile.
Specific Gravity (Water Displacement)
Pure gold is extremely dense (19.32 g/cm³). Weighing an item in air and in water lets you calculate its density — a clever at-home check for bars and coins. Tungsten fakes (tungsten has nearly identical density to gold) can defeat this test, which is why professionals combine methods.
Frequently Asked Questions
Is 24K gold better than 22K?
For investment, yes — 24K (.999+) is the standard for bullion, qualifies for the GST/HST exemption, and is the most liquid. For jewellery you wear daily, 22K or 18K is more practical because pure gold is soft and scratches easily. "Better" depends entirely on purpose.
What does 9999 mean on a Gold Maple Leaf?
It means the coin is 99.99% pure gold — among the purest bullion coins in the world. The Royal Canadian Mint pioneered this standard, and it's a point of national pride in the precious metals industry.
Is Canadian gold jewellery always marked accurately?
Legitimate Canadian jewellers must comply with the Precious Metals Marking Act, and enforcement is real. Problems arise mainly with secondhand pieces, market-stall sellers, and items bought abroad. When in doubt, have a jeweller test it.
Does higher karat gold tarnish less?
Yes. Tarnishing comes from the alloy metals (especially copper and silver), not the gold itself. 24K gold essentially never tarnishes; 14K and 10K can develop a patina over years, particularly with exposure to chemicals.
Can I convert my 14K jewellery into 24K bullion?
Indirectly, yes: sell your jewellery to a dealer or refiner (you'll receive its melt value minus their margin), then use the proceeds to buy bullion. You won't get a 1:1 exchange — expect to lose 10–30% in the conversion due to refining costs and dealer margins.
Why is some "gold" jewellery so cheap?
Because it isn't solid gold. Gold-plated (GP), gold-filled, and vermeil pieces contain only a thin surface layer of gold. They're costume jewellery, not investments. Always check for solid-gold hallmarks (10K and above) before paying gold prices.
Now that you understand purity, learn how premiums over spot price work in Canada — or check the live gold price to see what your gold is worth today.