10K Gold — The US Legal Minimum
10K gold is only 41.7% pure gold, alloyed heavily with copper, silver and other metals — the legal minimum purity that can still be stamped and sold as "gold" in most US states (some states set the bar even lower, but 10K is the common floor in practice). That lower gold content makes it the most affordable and scratch-resistant option, which is why it shows up on the cheapest end of chain and class-ring jewelry. This plays a similar market role to the UK's 9ct gold, but at a genuinely different purity (41.7% vs 37.5%) — not the same karat under a different name.
Other Karats & Related Pages
24K Gold
Stamped 24K
22K Gold
Stamped 22K
18K Gold
Stamped 18K
14K Gold
Stamped 14K
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Frequently Asked Questions
10K means the item is 41.7% pure gold by weight — the standard stamp for 10K gold, the lowest purity commonly recognized as "gold" for retail sale in most US states.
No. They serve a similar role as each market's lowest common purity, but 10K is 41.7% pure gold while UK's 9ct is 37.5% pure — a genuinely different purity, not a renamed equivalent. Compare using each site's own figure rather than treating them as interchangeable.