Metals · Co + Cr
Cobalt chrome
Updated October 16, 2026
Cobalt chrome is an alloy of cobalt and chromium, usually with some molybdenum, developed for jet engine parts and medical implants such as hip joints. For rings it has a bright white colour much like platinum without any plating, resists scratches better than titanium or gold, and weighs more than titanium, so it feels substantial. Unlike tungsten carbide, it can be cut off in an emergency.
- What it is
- Cobalt and chromium (about 28%), often with molybdenum
- Colour
- Bright white, no plating needed
- Used for
- Hip and knee implants, dental crowns, jet engine parts
- Density
- About 8.3 g/cm³: heavier than titanium, lighter than gold
Cobalt chrome vs titanium and tungsten
Titanium is lighter and greyer; tungsten carbide is harder and heavier but brittle and can only be cracked off. Cobalt chrome sits between them: whiter than titanium, tougher than tungsten (it bends rather than shatters), and scratch-resistant enough to keep its polish far longer than gold or platinum.
Sensitive skin
Medical cobalt chrome alloys are made for long contact with the body. Some cheap jewellery alloys sold as "cobalt" contain nickel, so if you have a nickel allergy look for "nickel-free cobalt chrome" on the listing.
The atoms inside
Shares are for the ASTM F75 alloy used in rings and medical implants. A simplified picture: real electrons are fuzzy clouds, not dots on rings, but the count in each shell is real. The cube shows how the atoms stack in the solid metal.
Electron shells from each element's ground-state configuration; crystal structures at room temperature. Source: electron configurations of the elements and crystal structures of the elements.
Real cobalt chrome pieces on Amazon
Each listing's own metal details were read on October 16, 2026 and match the title; we show its star rating, and leave out anything under 4 stars. Prices change, so the link goes to the live listing.
Cobalt chrome rings
Listed as cobalt chrome or solid cobalt.
Cobalt chrome comfort fit band, 3 mm 3 mm wide See it on Amazon → 
Cobalt XF chrome high-polish dome band, 6 mm 6 mm wide See it on Amazon → 
Boston Bay Diamonds cobalt chrome comfort fit band, 6 to 7 mm 6 to 7 mm wide See it on Amazon → 
Thorsten Caledonia flat polished cobalt chrome band, 4 mm 4 mm wide See it on Amazon → 
Manly Bands "The Novelist" cobalt chrome band 8 mm wide See it on Amazon → 
Accents Kingdom classic cobalt chrome dome band, 8 mm 8 mm wide See it on Amazon → Frequently Asked Questions
Is cobalt chrome better than tungsten for a wedding band?
For many people, yes: it is almost as scratch-resistant, it will not shatter if dropped on a hard floor, and it can be cut off in an emergency. Tungsten is harder and heavier but brittle.
Does cobalt chrome tarnish?
No. The chromium forms a protective oxide skin, as in stainless steel, so it stays bright white.