All About Iridium – Precious Metals Series

Do you have jewelry made out of iridium? This is quite rare and at over $900 per ounce as the current price, you may have a very expensive piece on your hands.

Quite rare, iridium is a brittle, hard member of the family of platinum. It has appeared commonly on fountain pen nibs, x-ray optics, and unmanned space crafts. In 2009, it was announced by American Elements that they would begin production of the first ever pure jewelry made of iridium. Its value typically is about $970 per ounce.

The Discovery of Iridium

In 1803, Iridium was discovered by Smithson Tennant, an English chemist in London. He found it in the remaining residue where aqua regia had dissolved platinum. Aqua regia is a mix of nitric acid and hydrochloric acid. At the same time, he also discovered osmium. The Latin word for iris is where the term Iridium comes from, which actually means rainbow. The reason for this is that there are many colors in its salts.

In rocks that date to sixty-five million years ago between the Cretaceous and Tertiary periods, abnormally high iridium amounts have been found. This led to a belief that a comet containing iridium may have struck the earth at that time, which led to the dinosaurs’ extinction and many other life forms.


Iridium is a brittle, lustrous, hard, rare and very dense metal like platinum. It is not very reactive chemically. It is a metal most resistant to corrosion and it resists any acid attack. Molten salts attack iridium such as sodium cyanide and sodium chloride. Generally, iridium is credited with being the element second-densest after osmium based on the density measured. Calculations that involve the space lattice of the elements show that there is more density in iridium.

Iridium uses

Iridium’s main use is as an agent for hardening allows of platinum. It forms an alloy with osmium that can be used for pen tips and bearing for compasses. Iridium is utilized for making equipment used at high temperatures such as crucibles. It is also used for making electrical contacts that are heavy-duty. Used in making international standard kilogram, this is an alloy of ten percent iridium and ninety percent platinum. Iridium radioactive isotopes are used for the treatment of cancer in radiation therapy.

Modulus of Elasticity

The modulus of elasticity of iridium is, among the metals, the second highest. Only osmium surpasses iridium in this respect. This, along with a low figure on the Poisson’s ratio and the high rigidity modulus, indicates a high tendency for stiffness and deformation-resistance that rendered its fabrications into useful components quite difficult. Even with the high cost of iridium and these limitations, many different applications have occurred in which mechanical strength is a factor essential in some of modern technology’s most severe conditions.