Gold lends itself to being easily alloyed with a number of different metals. Yellow gold is gold alloyed with silver and copper. In rose gold, the concentration of copper is higher, whereas, in green gold, it is silver that has the higher concentration. Red and pink gold are formed by varying the silver and copper amounts. White gold is an alloy with palladium or nickel. Blue gold is formed with indium or gallium; purple gold is made using aluminum.
Below is a table with different metals and the outcome of alloying them with gold.
| Metal | Purpose | Effect |
|---|---|---|
| Silver | Brightens color, hardens | Produces greenish-yellow gold; lowers cost |
| Copper | Hardens significantly | Gives a reddish tint; used in rose gold |
| Nickel | Whitens, hardens | Creates white gold (less common today due to allergies) |
| Palladium | Whitens | Premium white gold; hypoallergenic |
| Platinum | Increases density and durability | Rarely used in large amounts because of cost |
| Zinc | Improves casting | Helps reduce oxidation during melting |
| Cadmium | Lowers melting point | Historically used; now largely avoided because of toxicity |
| Indium | Improves ductility | Specialty applications |
| Gallium | Alters melting behavior | Specialty alloys |
| Iron | Magnetic alloys | Experimental and niche uses |