- Jewelry Identifier
- Gold alloys
- 18K Yellow Gold
* 18K gold
18K Yellow Gold: what it's made of, its purity, and its value
Premium standard worldwide. Warm rich yellow tone. Copper-to-silver ratio adjusted for tone and casting properties.
Published May 30, 2026
Quick facts
- Karat
- 18K
- Purity
- 75.0%
- Fineness
- 750/1000
- Color
- Yellow
- Density
- 15.45 g/cm³
- Melting point
- 905 °C
What it's made of
- Gold
- 75%
- Silver
- 12.5%
- Copper
- 12.5%
The gold content is fixed at 75.0% — that's what makes it 18K. The remaining metals are what set the color: Silver and copper are added mainly for hardness; they leave the warm yellow of the gold largely intact.
About 18K Yellow Gold
Premium standard worldwide. Warm rich yellow tone. Copper-to-silver ratio adjusted for tone and casting properties.
How much it's worth
The melt value of a 18K Yellow Gold piece is gold spot price × 0.750 × weight (g), because only 75.0% of the metal is gold. A buyer then deducts roughly 5–15% for refining and margin, so a cash offer lands just under that figure. Higher-karat gold packs in more gold per gram, so it carries a higher melt value — but it's also softer and scratches more easily, which is why everyday jewelry often uses lower karats.
* Frequently asked
FAQ
- Q. How much gold is in 18K Yellow Gold?
- A. 75.0% by weight. 18K means 18 parts gold out of 24, which works out to 750/1000 fineness — the rest is alloy metals added for color and durability.
- Q. Is 18K Yellow Gold real gold?
- A. Yes. 18K is genuine gold — it's 75.0% pure gold by weight, alloyed with other metals. It is not gold-plated or gold-filled; the gold runs all the way through.
- Q. Why is 18K Yellow Gold yellow?
- A. The color comes from the metals mixed with the gold. Silver and copper are added mainly for hardness; they leave the warm yellow of the gold largely intact.
- Q. Will 18K Yellow Gold tarnish or cause skin reactions?
- A. Solid 18K gold doesn't tarnish, and this alloy is nickel-free, so skin reactions are rare. Surface films usually come from skin oils or lotions and wipe off with a soft cloth.
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