Nickel and Cobalt are always found together, and are rarely seperated due to cost. Cobalt is used as binding agent in metal alloys and is a naturally ocurring metal found in soil. People can have an allergy to cobalt and believe it to be nickel, or sometimes both. It is much more common to be a nickel causing the allergy though. The way to reveal this is by 'patch testing' at your doctors. Basially a technique wherebya small amount of an element are put onto the skin for a period of time to see if an allergic reaction occurs. All the symptoms and facts pertaining to nickel, it's treatment and avoidance, throughout this site are the same for cobalt.