platiniridium

alloy

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July 2, 2026

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Platiniridium is an alloy primarily composed of platinum and iridium, typically containing 1% to 30% iridium. This alloy is significantly harder, stiffer, and more chemically resistant than pure platinum. It is also highly resistant to high-temperature electric sparks, making it suitable for electrical contacts and sparking points.1

Historically, the international standard for the meter and the current standard for the kilogram of mass were constructed from a specific platiniridium alloy containing 90% platinum and 10% iridium. Platiniridium can also occur naturally as a mineral, which is a natural alloy of iridium with platinum and other related metals.12

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iridium
…to 77 percent iridium, in platiniridium up to 77 percent, in aurosmiridium 52 percent, and in native platinum up to 7.5 percent. Iridium generally is produced commercially along with the other platinum metals as a by-product of nickel or copper production.
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…to 77 percent iridium, in platiniridium up to 77 percent, in aurosmiridium 52 percent, and in native platinum up to 7.5 percent. Iridium generally is produced commercially along with the other platinum metals as a by-product of nickel or copper production.
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platinum
…the very rare native alloy platiniridium. Platinum occurs combined with arsenic as sperrylite (PtAs₂) in the copper–nickel mining district near Sudbury, Ontario, and with sulfur as cooperite (PtS) in the Transvaal. (For information about the mining, recovery, and production of platinum, see platinum processing.)
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…the very rare native alloy platiniridium. Platinum occurs combined with arsenic as sperrylite (PtAs₂) in the copper–nickel mining district near Sudbury, Ontario, and with sulfur as cooperite (PtS) in the Transvaal. (For information about the mining, recovery, and production of platinum, see platinum processing.)
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