The word cobalt comes to English in the late 17th century: from German Kobalt ‘imp, demon’ (because the presence of cobalt-bearing ore made it more difficult to extract silver, and miners believed that it was harmful to the silver ore with which it occurred). 

• Cobalt is used in many applications, including:

  • Cancer treatment: Cobalt is used as a tracer and for radiotherapy. 
     
  • Batteries: Cobalt is used in the cathodes of lithium ion batteries, nickel-cadmium batteries, and nickel-metal hydride batteries. 
     
  • Alloys: Cobalt is used in superalloys for jet engines and in alloys for prosthetic hip and knee replacements. 
     
  • Cutting tools: Cobalt is used in tungsten carbide for cutting tools. 
     
  • Petroleum industry: Cobalt is used in catalysis to produce clean fuel. 
     
• Food

  Cobalt is found in healthy foods like fish, nuts, green leafy vegetables, and cereals. 

   

  Natural abundance

  Cobalt makes up 0.0029% of the Earth's crust. It's not found on the Earth's surface because it reacts with oxygen in the atmosphere. 

   

  Toxicity

  Cobalt can be toxic to humans in large quantities. 

Just the facts:

Cobalt Definition & Meaning - Merriam-Webster