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Why does gold stay shiny instead of tarnishing or rusting?

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A diagram showing the periodic table entry for gold, with the symbol Au, atomic number 79, atomic weight 196.96657, electron configuration, and labels for its properties as a solid transition metal with a face-centered cubic crystal structure. — gold The precious metal gold is a chemical element with the symbol Au. Its square on the periodic table details some of its properties, including its atomic weight, atomic number, and crystal structure.

Gold remains shiny and resists tarnishing or rusting because it is a noble metal, meaning it possesses an outstanding resistance to oxidation and chemical reactivity.1

This inertness is primarily attributed to gold's stable electronic configuration, which features completely or nearly filled inner d orbitals. These filled subshells confer a strong resistance to electron loss, resulting in high ionization energies and a reduced tendency to undergo oxidation when exposed to oxygen, water, or other environmental elements.21

Because of this low chemical reactivity, gold does not readily corrode or form oxides, allowing it to maintain its characteristic metallic luster over long periods. While gold is not entirely nonreactive—it can be dissolved by strong oxidizing agents like aqua regia—it remains one of the least chemically reactive of all transition elements.21