Iridium

Real Metals · Very Rare · Modern

The most corrosion-resistant metal known. Iridium survives concentrated acids that dissolve everything else. The second densest naturally occurring element, its extreme hardness makes it virtually impossible to work with conventional tools.

Identity

Symbol
Ir
Atomic number
77
Source
Natural element
Aliases
Ir

Physical Properties

Appearance
Silvery-white with a slight yellowish tinge, extremely hard, the second densest element after osmium
Luster
Metallic
Density
22.56 g/cm³
Melting point
2446 °C
Boiling point
4428 °C
Lighter
Platinum
Denser
Osmium
Magnetism
Non-magnetic
Electrical conductivity
Medium

Mechanical Properties

Mohs hardness
6.5
Tensile strength
2000 MPa
Softer
Titanium
Harder
Vanadium
Workability
Difficult
Brittleness
Brittle
Malleability
Very Low
Ductility
Very Low

Chemical Properties

Corrosion resistance
absolute
Reactivity
very low

Lore & Narrative

An iridium-rich layer in sedimentary rock worldwide marks the precise moment of the Chicxulub asteroid impact 66 million years ago. The metal is rare on Earth's surface because it sank to the core during planetary formation. The iridium we mine arrived via asteroid impacts after Earth solidified.

Notable uses
Spark plug electrodes, scientific crucibles, international prototype kilogram alloy
Forge uses
precision instruments, extreme environment applications
Worldbuilding traits
indestructible, meteoric, rare, extreme

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