Cobalt is an alternative metal, white color, harder than platinum, and similar to platinum appearance. Cobalt is not a precious metal. It was detected in early Egyptian sculptures and Persian jewelry from the third millennium B.C. The word cobalt is derived from the German phrase "kobald ore" which means "goblin ore". In 1938, cobalt-60 was discovered and mainly used for medicinal purposes. Most recently with high gold and platinum prices, jewelers began to use cobalt to create wedding rings. Cobalt is more scratch resistant than titanium and other precious metals. It can be sized slightly without cutting into the ring. The weights of cobalt rings are very similar to the weight of gold rings. Cobalt does not contain harmful alloys and as of today does not cause any allergic reactions. Unlike titanium and tungsten carbide, cobalt can be cut off in emergency cases. It is natural and tolerated by the human body. Cobalt has been used for years in the medical field.
Significant cobalt ore deposits exist in Australia and Africa.
Physical Properties of Cobalt
- Melting point: 1768 degrees K
- Symbol: Co
- Crystal System: hexagonal
- Hardness: 5.0 Mohs'
- Cleavage: None
- Fracture: None
- Specific Gravity: 8.9
- Color: gray metal, metallic gray