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Does iridium tarnish? Does it rust, corrode and oxidize?
No, iridium doesn’t tarnish. It’s one of the most corrosion-resistant metals known to mankind and is resistant to tarnish, even at high temperatures.
Iridium is unaffected by air, water, and most acids. And while it can react with oxygen at high temperatures and form iridium dioxide, that’s still not tarnish and corrosion as seen in other metals.
Learn more below, especially if you own or want to own pure iridium bullion or jewelry.
- Does Iridium Tarnish? Does it Corrode, Rust and Oxidize?
- Does Pure Iridium Bullion Tarnish? Does it Corrode and Oxidize?
- Does Pure Iridium Jewelry Tarnish? Does it Oxidize and Corrode?
Here’s an awesome quiz about iridium tarnishing and corroding. Take it after you’ve read my guide.
Table of Contents
Does Iridium Tarnish? Does it Corrode, Rust and Oxidize?
No, iridium doesn’t tarnish. It’s a noble metal that’s highly resistant to all of the Earth’s elements + anything you can expose it to in your home and kitchen.
I list below all the potential tarnishing-causing substances and their effect on iridium objects.
- Water. Iridium doesn’t tarnish in water. Water has zero effect on iridium regardless of the exposure time Saltwater and chlorinated water also don’t tarnish iridium so it’s safe to wear iridium jewelry while swimming in the ocean.
- Fire. Fire doesn’t tarnish and corrode iridium. Iridium bullion and jewelry can easily survive even the hottest housefires.
- Bleach. Bleach doesn’t tarnish and and corrodes iridium. While ruthenium, a related platinum-group metal, will quickly dissolve in bleach, iridium will stay unchanged.
- Hydrogen peroxide. Iridium doesn’t tarnish in hydrogen peroxide. Iridium is highly corrosion-resistant and hydrogen peroxide has little to no effect on it. In fact, you can use iridium as a catalyst for the decomposition of hydrogen peroxide.
- Toothpaste. Toothpaste neither corrodes nor tarnishes iridium. The abrasive substances in toothpaste are far too weak to do any damage to iridium-made items.
- Vinegar. Vinegar doesn’t tarnish iridium. Vinegar’s acetic acid is too weak to tarnish, corrode and oxidize iridium, even upon prolonged exposure.
- Lemon juice. Lemon juice doesn’t tarnish and rust iridium. It also doesn’t oxidize and corrode it. Lemon juice’s acids are weak and unable to do any visible damage to pure iridium objects.
- Makeup. Makeup has no effect on iridium. It doesn’t tarnish, corrode, oxide or rust objects made of pure iridium.
- Nitric acid. Nitric acid doesn’t tarnish iridium. It also doesn’t oxidize and corrode it.
- Alcohol. Alcohol doesn’t tarnishes or corrode iridium. You can use rubbing alcohol (isopropyl alcohol) to clean your iridium jewelry and bullion.
Pure iridium is the most tarnish and corrosion resistant metal in the world. Almost no substance on our planet can change it chemically. This includes aqua regia which can dissolve gold like it’s nothing.
There’re some notable exceptions though. Hydrochloric acid dissolves iridium when it’s combined with a strong oxidizing agent like chlorine gas or with sodium perchlorate. Additionally, molten sodium cyanide (NaCN) and potassium cyanide (KCN) also dissolve iridium.
These severe reactions only happen in controlled conditions in chemical labs and can never happen under normal circumstances and in normal households.
You have nothing to worry about if you own iridium bullion or jewelry. In practical terms they’re indestructible.
Does Pure Iridium Bullion Tarnish? Does it Corrode and Oxidize?
No, pure iridium bullion doesn’t tarnish. It neither corrodes nor oxidizes.
Coins and bars made of pure iridium that you own are safe from tarnish and corrosion as long as you don’t bathe them in hydrochloric acid as hydrochloric acid is a rare substance that can dissolve iridium.
But you’d need to be a chemist to even have the opportunity to test iridium’s resistance to this acid.
Does Pure Iridium Jewelry Tarnish? Does it Oxidize and Corrode?
No, pure iridium jewelry doesn’t tarnish. It also doesn’t corrode, rust or oxidize. Iridium jewelry is as steadfast as time itself and will last you forever with minimum upkeep.
Pure iridium doesn’t tarnish, but iridium alloys used for jewelry making exist and some of them are more prone to tarnishing and corrosion than pure iridium alone.
- Pt-Ir (90/10). Contains 90% platinum and 10% iridium. Platinum doesn’t tarnish and platinum doesn’t corrode and oxidize.
- Pt-Ir (95/5). Contains 95% platinum and 5% iridium. The same as above.
- White gold with iridium. Small amounts of iridium (usually less than 2%) are added to white gold alloys to improve hardness. White gold doesn’t tarnish.
- Osmium-iridium. Natural alloys that can be used in specialty pen nibs and high-end watch pivots. Osmium doesn’t tarnish and corrode.
Does Iridium Tarnish? Does it Corrode, Rust and Oxidize? Conclusion
Iridium doesn’t tarnish. It’s one of the most corrosion-resistant metals known to mankind and is resistant to tarnish, even at high temperatures.
Iridium is unaffected by air, water, and most acids. It can react with oxygen at high temperatures and form iridium dioxide, that’s still not tarnish, rust and corrosion as seen in other metals.
References:
- Does an iridium-gallium alloy tarnish?- https://www.quora.com/Does-an-iridium-gallium-alloy-tarnish
- What’s Iridium and why is it significant?- https://www.reddit.com/r/askscience/comments/22xjz4/whats_iridium_and_why_is_it_significant/
- Iridium: What it Is, Applications, Example- https://www.investopedia.com/terms/i/iridium.asp
Nikola Roza
Nikola Roza is a blogger behind Nikola Roza- SEO for the Poor and Determined. He writes for bloggers who don't have huge marketing budget but still want to succeed. Nikola is passionate about precious metals IRAs and how to invest in gold and silver for a safer financial future. Learn about Nikola here.
